Tuesday, February 26, 2008


Knock... knock.... Is anybody still there? You didn't all leave yet, did you? You didn't wait for me to come out from underneath my rock? Oh well. I guess I have to start building my readers base from scratch. If you did hang around waiting for me, thanks. I usually bounce back pretty quickly after disaster strikes, but it took me a while this time. And I may still not be entirely my old self, but that may have more to do with the horrible cold virus I've contracted than continued depression due to not passing the oral exam.

Over the past week and a half or so, I've been puttering around the lab, mainly doing stuff that I would have to do anyway, no matter what my decision is. Like cleaning up, organizing my samples, gathering my data, and such. My adviser is his usual friendly, happy self, full of encouragement. One of his best friends in the department, who is also on my committee, urged me to go on. He insisted that it's feasible to finish, and he agrees with my adviser on what I need to do to finish. Now, if we could just get the rest of the committee to agree....

A few minutes ago, I sent out an e-mail asking which dates int he end of March would be good to re-do my exam. That is a decision of sorts. At least it means I'll be taking the exam again. I reserve the right to bail out any time I feel like it, though, and call the whole thing off.

The thing is, what else would I do with myself? I'd be miserable at home, being in the lab is what I do best, it's what I love to do. So, gradually, I've re-entered the lab, even though I mainly do housekeeping right now. I have to write up a report on everything I've done so far, which is essentially the second chapter of my (intended) dissertation. If it wasn't for the nasty bug I caught, I might have made some progress on that.

On top of that, I'm leaving town for a few days and will not be back until Saturday afternoon. So, I'm putting any major things on hold until then. Meanwhile, I expect to be back to blogging as usual from now on. Glad you stuck around!

Wednesday, February 20, 2008

Science standards

In the good news department Florida's board of education passed the new science standards yesterday with minor changes. Instead of "evolution" the wording was changed to "the scientific theory of evolution." In my opinion that makes the wording even stronger, not a compromise. That emphasizes that we're not talking "just a theory" here. The vote was 4-3 , which shows how necessary the standards are.

What I thought was interesting is that during the discussions, there were those that wanted "Intelligent Design" taught as an alternative theory to that of evolution, and that the arguments were outright religious. People were note really trying to pass ID as another scientific theory, they simply stated their religious belief as the reason for their objection to the teaching of evolution. And they feel that religion has a place in every part of their lives, including science education. It's hard to believe.

Monday, February 18, 2008

To PhD or not?

On Friday, P1 and I had lunch with my adviser. He thinks I should continue, re-take the exam, and finish up. I explained to him that the exam is the least of my problems. If I had known the kinds of questions to expect, I would have studied for it and aced the exam. I *do* object to the singing faculty member on my committee, however. I never wanted him on my committee to begin with, but my adviser insisted. I should have put my foot down at the time, but I did not. I don't think I should have to put up with being humiliated during my oral exam, and I'm decidedly uncomfortable about the idea of him being there for any other exams.

The biggest problem, however, is the question of what it's going to take for me to graduate and whether that is feasible this year. He asked me to write up a summary of what I've done so far, and include all my negative results (that'll be a big report!). He also wants me to write up and name the chapters I'm planning to include in my dissertation. I asked what *he* expects me to do, and he reiterated everything we've talked about for the past year or so. I've changed directions with his permission, so I'm glad he is sticking with that. Although he could have mentioned that during the exam, when committee members were coming up with all sorts of interesting ideas of where my research should be heading. At least one other committee member is on board with these plans, but even if the singing member does a disappearing act, that still leaves 2 more members to be convinced that this is worthwhile.

My adviser told me to write it up, and he'll take it to the other two and explain the plan to them. I'm still torn. On the one hand I think I'm fully capable of doing this, and as long as we stick to the plan, it is feasible. Tough, but feasible. But if significant stuff is added to my project, that will become a problem in terms of funding and immigration status. And if it is impossible, I really don't want to waste any more of my time being tortured in exams.

So far, my dissertation plan looks like this:
Chapter 1. Literature review
Chapter 2. Original project that yielded negative results
Chapter 3. New direction that is looking promising
Chapter 4. Side project I did for my boss last year

I can write chapter 1 now. Chapter 2 needs a little more data to finalize it, but that can be done in about a month, and I can still do other stuff in that month too. I could start on chapter 4. All the data is in, I will need to do a bit more analyzing for that, but I will do that anyway, because my adviser wants me to present it at a meeting in July. That leaves chapter 3. I'll need about 6 months to finish up chapter 3, but that doesn't seem unreasonable. In terms of publications, I should get a (small) paper out of chapter 2, and a couple out of chapter 3. For technical reasons, chapter 4 is not publishable at this time.

Yesterday my adviser said he wanted singing member to stay on my committee. The problem is that if I ask him to step down and he refuses, I have to petition to the graduate school to have him removed. And that simply is not my style. And if I fail, I have a completely disgruntled singing member present during my exams. Talk about a disaster.

Slowly, I'm coming out from underneath the rock I've been hiding under for the past few days. I've basically ignored all questions, and just told everyone I didn't want to talk about it. And I hid in my office. I guess I should head out into the big world, but I'm not ready yet. I need more time.

Friday, February 15, 2008

I failed

Or to put it differently, I did not pass. I've been given the option to re-take the exam again in 2-3 months. At this point I'm not in the right frame of mind to make a decision on that, but I think I'd rather not.

The whole experience was horrible. It went wrong right from the start, I lost my confidence in a big hurry, and it all went downhill from there on. I had imagined that the questions would be an extension of my written exams, and had read over those before the orals. However, my committee members hardly touched on that. They asked me a lot of questions that I should have known the answers to, but I didn't or I stumbled too much. My confidence level had gotten so low, that even if I did know the answer, I didn't say it quickly enough.

At some point one of my committee members asked me something and it could be one of two answers. I told him I didn't know the answer, he asked me to guess, and of course, I guessed wrong. He then told me I had just missed the 1-million dollar question. A few minutes later, I was not answering quickly enough, he started singing the Jeopardy theme song, played during "Final Jeopardy." It was a disaster.

Moreover, my previously expressed concerns about the direction of my project, and the disparate opinions in my committee, were definitely justified. Nothing has changed there. I suppose I did a really shitty job of "selling" myself. I was never a good salesperson. If I had been, I would have gone into sales. As a result, I was unable to effectively convey what I have accomplished so far, and why it's a good thing. There are widely varied opinions on what I need to do next, and I run out of funding in December, and my immigration status runs out in August. I can possibly get another immigration status extension until December, but I don't think it will be extended any further. If I work really, really hard, I might be able to satisfy one of the committee members' demands, but there is no way I can satisfy all of them. And the work I did the last 9 months seems of no interest to most of them, a total waste of time.

So, since I now know what they want to ask me, I can probably study up on those topics in a few days and re-take the oral if I was so inclined. However, I don't think I would want to sit in front of that same group of people again, and be that humiliated. And even if I did, that still would not shed light on the much more important question: is there anyway that I can fulfill the requirements for a PhD program? I don't honestly know the answer to that.

I also feel a little betrayed by my adviser, who really is the nicest guy, but who should have stopped the unprofessional behavior of the singing committee member, which only made me more nervous. Truth be told, they asked fair questions, and I didn't know the answers, so I did not deserve to pass. I do not think it has to do with a lack of intelligence on my part. I think it has more to do with not meeting their expectations. For some reason they all had really high expectations of me, and I disappointed them, and that includes my adviser.

I love doing science more than anything, and I would really suck at being a stay-at-home mom. I guess I have the option of sticking around here as my husband's dependent, but I would not be allowed to work, and that is simply not an option for me. We'll have to seriously consider our options, and right now, leaving the country seems like a good one to me.

My adviser wants to have lunch with me today, and I'll probably go even though I got about 2 hours of sleep last night, and my eyes are read and puffy of all the crying (yeah I know, I'm an emotional wreck, disgusting!). I don't know what to tell him. Otherwise, I'm not really in the mood for anything.

Thursday, February 14, 2008


It is distracting to read this on the morning that I am supposed to prepare for my oral qualifying exams. Yes, I know, I should read my written exams instead of atheist blogs, but they are the oasis of reason in this world of religious extremism, so I need my daily fix of sanity.

The Friendly Atheist helps spread the tale of the woman who was not allowed to be the referee in the men's basketball game, because a woman can not be put in a position of authority over boys because of the academy's believes. Un-effing-believable. Do they know it's the 21st century? I hope she sues the pants off of them. I'm not at all in favor of frivolous lawsuits, but this stupidity will only stop when the perpetrators are reached where it hurts them... in their bank accounts.

So much for my fix of sanity this morning.

Note added later: Apparently the woman in question has been thoroughly brainwashed by her old-fashioned institution. According to Fox News she has said that she is not angry at her school, and does not wish to take the matter any further. This is why change is so slow. Compliance to insanity does not improve changes of insanity going anywhere anytime soon.

Wednesday, February 13, 2008

Things are never simple

After the torture of written exams, it is finally time for my oral qualifying exam *tomorrow afternoon*. Since it is really hard to prepare for an oral exam, I was planning to look over my writtens (the first on of which I wrote 3 months ago), but mostly focus on getting some more research data. I was scheduled to process samples from my last experiments, and it would be tight, but possible. Then... F1-3 woke up with a fever. She hardly slept at all last night, whining, complaining, coughing. I'll probably take her in to the pediatrician today, just to make sure she doesn't have another case of strep throat, which would be treatable. Most likely it's a cold, and she just has to get over it. But if it is bacterial, she needs antibiotics in a hurry. Either way I'm screwed for tomorrow. P1 might just have to take her to work with him, which should be interesting.

Things are never simple, are they?

Update: Luckily, it is treatable, F1-3 has (yet another) ear infection. It saddens me to think she must have been in pain. The swift action of antibiotics should take care of this by tomorrow, and she can go to daycare, and I can turn off my phone during my exam.

Friday, February 8, 2008

Sustainable agriculture

No more written exams! Yeah!!! My last written qualifying exam lasted for 4 1/2 hours, and consisted of 4 questions. Three of them were easily answered using the posts I put up 2 days ago (blogging my study results actually proved useful). Nutrient deficiencies were featured prominently, as was postharvest longevity of flowers. Three of the questions were polished off in about half an hour. I spent, however, 4 (!) hours writing on the first question which came completely out of left field. I received a thick stack of printouts with the draft standards for sustainable agriculture, and had to write 4 papers on these. The standards propose to work towards completely organic production systems, which (among other things) would not allow use of genetically modified organisms (GMOs), and gradually eliminate synthetic chemicals from production systems. I had to write a paper in support of the standards on GMOs, one opposed, one in support of the standards on the elimination of synthetic chemical use, one opposed.

It wasn't easy for me to write these papers. I was forced to treat the issues as black-and-white, which clearly, they aren't. I was not asked to form and write on my own opinion. There are arguments pro and con these standards, and I had to simply separate the pros to put in the papers in support of the standards, and vice versa, put all the cons in the paper opposed to the standards. There was no argument involved, no battle of the mind, no final conclusion to be drawn. That bothered me. Of course, I do have an opinion, and at some point I thought my arguments in two of the papers (those were I argued against my own position) became rather silly.

[Credit: Purdue Agriculture Connections]

In my opinion it is naive to think that the standards will be feasible in large-scale agriculture with our current level of understanding, and our current knowledge on integrated pest management. There were darn good reasons to introduce chemicals, one of them being that without those, you're large-scale monocultures are bound to be destroyed occasionally by a pathogen or pest. This would come at a great price financially, socially, and politically. Although you'll be hard-pressed to find someone who thinks we should apply as many pesticides and other chemicals as humanly possible, it's not too hard to find people who are of the opinion we shouldn't use any at all. However, it is not realistic to think that we can basically maintain current production levels while eliminating the use of all synthetic chemicals and pesticides; they do serve a valuable function in agriculture today.

Organic production can work fairly well on a small-medium scale, but with the level of technology available today, is not yet feasible on really large scale. That's not to say we cannot work towards that. We most certainly can, and we most certainly should, and hopefully at some point in the future we can reach this admirable goal, but we're not quite there yet. Unless we're willing to put the livelihood of producers at risk.

[Credit: Wikimedia commons]

For example, the use of synthetic fertilizers allows us to add, very specifically, the exact amount of nutrients that we need. No more, no less. Replace that with something like cow manure (see picture), and the composition varies from one batch to the next, and you have to apply the whole thing, which also applies nutrients you already have enough of. Let say we have used the scientific knowledge of today to sample the plants in our field, and analyzed the nutrient content of the crop, and determined that it is low in nitrogen, but it has plenty of phosphorus and potassium. These are the 3 macronutrients routinely supplied in synthetic fertilizers (which means they were chemically produced in a factory). Now, we can add synthetic fertilizer containing only nitrogen, and since we know how much is in the plants, we know how much there needs to be, we calculate how much we are likely to loose in the soil because of leaching (even after we make every effort at our disposal to minimize leaching), and we apply the amount of nitrogen we need. We apply it near the plant, so that the roots will have optimal access to the nitrogen we've supplied, and we're careful not to apply it too far from the plants so as not to waste it. Had we instead applied cow manure, we would have had to calculate how much to add to satisfy our nitrogen requirements, but we would also be adding phosphorous and potassium, which our crop already has enough off. We risk overdosing on those nutrients (at high levels, toxicity symptoms become apparent), we waste valuable nutrients, because we don't really need any more, and we unnecessarily contaminate the groundwater with excesses of phosphorous and potassium. Virtually every organic fertilizer has the same problems, having the potential to increase groundwater contamination, and not because the source is organic, does that become any less of a problem. Would you still consider that sustainable agriculture?

You may say, but in floriculture, surely we can do without all those synthetic hormones that you apply to regulate plant height and flowering, like you described here? Surely that is frivolous. The reality of the capitalistic ideas of supply and demand, and consumer satisfaction, dictates that plants of irregular heights, that are not flowering (or not flowering synchronously) at the time of display, will be less desirable than those that are perfectly sized for their container, with a beautiful, abundant display of flowers across the board. Uniformity of the crop cannot be taken for granted in today's floral industry.

[Credit: Dr. Bob's Gardening Tips]

For example, the requirements for size, plant height, number of flowers, and availability of plants for poinsettia (Euphorbia pulcherrima) around December are extreme. On December 24, a poinsettia plant may be worth $12, after the holiday season, it's worth $1. You can hardly imagine all the hoops growers have to jump through to satisfy these extreme demands from consumers. From selection of desirable cultivars, exact scheduling of their crop depending on the growth conditions and how vigorous the cultivar grows, regulating day/night conditions, making sure the temperature is exactly right to prevent growing too much or not enough, application of very carefully calculated and applied fertilizers according to the regulations, scouting and treating for pathogens and pests also according to all the EPA regulations, pinching at the exact right time to allow enough leaves to grow, monitoring growth and applying growth regulators if the plants grow too fast or too slow for the schedule, monitoring and adjusting of the alkalinity, pH, and EC of the growth medium, to packaging, shipment, and meeting deadlines and quality standards of the retailer. The retailer will not buy a crop of poinsettia's that does not conform to the strictest of standards. A plant that is 1 inch over the desired height is practically worthless. So, if you measure your plants throughout the growing process (which growers do), and you see that (some of) your plants are growing too fast, too tall. You get off your butt, follow all the safety requirements, get yourself some cycocel, B-nine, or Bonzi, and do what you need to do to save your investment. If some of your plants are too small, some too large, and others ok, your retailer will send you packing, because you have agreed to X number of plants of Y height all in full bloom on the second Monday in December, and you've delivered a hodge podge.

[Credit: University of Illinois extension]

The value of flowers, more than that of any other agricultural commodity, is extremely sensitive to the presence of a ubiquitous fungus like Botrytis cinerea. A few botrytis or powdery mildew spores on your roses (see picture), and your crop drops to the value of $0. Not spraying, is simply not an option. By the way, B. cinerea is very indiscriminate. It is not very particular about its source of nutrition, and it spreads very easily, all the nice little black dots are spores. Millions of them.

[Credit: Cornell University Cooperative Extension]

You've got to be a plant pathologist to say "that's just gorgeous!!" This is reaction not uncommon among my colleagues. A former colleague did not remove a branch from her pear tree for the longest time: "it has such beautiful fireblight symptoms!" I myself, am guilty of maintaining a pot of Magilla perilla, because it was such a fabulous example of downy mildew symptoms (luckily winter decided that I had no right to do so and killed it). All I have left of it are the slides I made and the pictures I took.

But I digress, this is bound to happen once I start talking plant path. I think I've made my point. There are valid reasons to use synthetic chemicals. In an ideal world we would grow all our crops organically. But sadly, contrary to Voltaire's insistence, this is not the best of all possible worlds, and for the immediate future, we're stuck using chemicals. As for the GMOs? That's another post entirely.

Thursday, February 7, 2008

Legal protection of cultivar propagation

The fifth and last installment in this series covers the legal mumbo jumbo that is involved in the right to propagate and sell ornamental plants. The information here is summarized from my own notes taken in a class I took, and is not in any way, shape, or form intended to be legal advice. Now that I have that disclaimer out of the way, it's time for more teaching-and-learning in order to maximize my performance on tomorrow's today's exam. I finished this part around midnight, at which point my internet connection-which had been spotty since 11 pm-completely went out. I spent an hour and a half trying to fix it, only to find out that my internet service was down. I called the company at 2 am and went to bed. When I woke up, service had returned, which is why it only gets posted now.

Part 1-Plant growth medium
Part 2-Nutritional deficiencies
Part 3-Plant growth regulators
Part 4-Post-harvest longevity of flowers

[photo credit: Aggie Horticulture at Texas A&M University]

Let's say Makita's Perpetual Flowers has developed a new cultivar of her beloved Alstroemeria's (Makita and P1's wedding flowers, hi sweetheart!!)*. They could easily be propagated either vegetatively or by seed. Should I sell them through my seed division or through my vegetative division? Let’s say I decide to use the seed division. Darn it! Now everyone is going to be able to just take the plants that I have worked so long on to make just *perfect* and make their own exact copies by propagating vegetatively, and sell it way cheaper than mine. They can, because they didn't have to spend years developing it. They just bought a few of my flowering plants at $50 per plant (did I mention they were *perfect*?), propagated them in their own greenhouses, and now they’re selling them for $20 each. I could get a Plant Variety Certificate, which would give me the exclusive right to propagate them by seed. Now, even if someone does manage to propagate my beloved flower plant vegetatively, they would not be allowed by law to propagate or sell “Perpetalstro.” This option is only available to me because the plant is new (I'm the intelligent designer here), its unique and clearly distinguishable from other closely related cultivars, and I can reliably reproduce this plant to get offspring with the same wonderful characteristics. For 20 years I'm the only one that can propagate and sell Perpetalstro.

If however, I decide to sell it through my vegetative division, I could patent it, which offers protection by the 1930 Plant Patent Act. That'd be great. I have a patent, and no one can propagate it vegetatively. I have the parents, and I'm definitely keeping their identity a secret, and no one is allowed to propagate it vegetatively. This should be fairly failsafe. But a patent has a limited life span, 20 years, to be exact. After the patent is expired, anyone can propagate and sell as many of my beloved plants as they want. Of course, I'd have to make sure that none of the people working with me disclose the parents, because the Plant Patent does not prevent anyone else to make the same plant by creating their own hybrid from the same parental plants.

This ends the 5-part series written to help me do my last written qualifying exams which starts 7 1/2 hours from the time I write this. Now I'm off to get some zzzzzzzzzzz's. In the morning I will print the series out, read them over it one more time, and then head straight for my exam.

* This is actually not a good plant genus to use as an example, because Alstroemeria's are naturally cross-pollinators (meaning the mommy and the daddy plants are different individuals). This means that any plants you would get out of the seed would not have all the same desirable traits as the hybrid parent did, all the little baby plants would look different. Sort of a natural way to prevent people from reproducing your Perpetalstro. But I'm using it as an example, because I love Alstroemeria. It's our wedding flower (yoohoo honey!!), and right this moment I have a vase of senescing specimens right in front of me.

Wednesday, February 6, 2008

Postharvest longevity of flowers

Keeping flowers beautiful for as long as possible is crucial to the floriculture industry, since consumers would probably buy less of the really old-looking, wilted flowers, than they do of the pretty, fresh flowers. This is the topic of installment 4 of the makita-prepares-for-exam

Part 1-Plant growth medium
Part 2-Nutritional deficiencies
Part 3-Plant growth regulators
Part 5-Legal protection of cultivar propagation

Many factors influence flower longevity, and they differ from one plant species to another. More than simply a question of more revenue for growers, flower longevity increases the chances of cross-pollination by insects (Primack, 1985). In many plants, senescence (wilting and dying) of flowers is enhanced by the plant hormone ethylene (hence the use of plant growth regulators to remove flowers from the plant, see part 3).

An interesting paper by Torre et al. (1999) linked low relative humidity during rose production, with higher calcium (Ca) content and delay of senescence. They propose that Ca protects membrane proteins and phospholipids from degradation. This prevents the cell membranes from breaking down and releasing ethylene, which results in continued transport of water nutrients and keeps the cells alive longer. Cool! Could you feed your roses calcium (you know, put some chalk shavings into the vase)? Well, I haven't tried chalk shavings, but apparently calcium chloride does the job, at least according to these scientists.

Application of carbohydrates (sugars), cytokinins, and gibberellins also seems to increase flower longevity (Leonard & Nell, 2004; Wingler et al, 1998). In Alstroemeria (the flowers at my wedding, hi honey!!!), which is normally classified as insensitive to ethylene for induction of senescence, a very small, but consistent amount of ethylene is produced just before the flower falls off (Wagstaff et al., 2005). It looks as if the flower is normally insensitive, but becomes sensitive to ethylene just before this abscission, and that ethylene is produced right at that time.

Leonard, R.T., and Nell, T.A. (2004) Short-term pulsing improves postharvest leaf quality of cut oriental lilies. HortTechnology, 2004. Vol 14, pp. 405-411.

Primack, Richard B. (1985) Longevity of individual flowers. Ann. Rev. Ecol. Syst. Vol 16, pp.15-37.

Torre, S., Borochov, A., and Halevy, A.H. (1999) Calcium regulation of senescence in rose petals. Physiologia Plantarum. Vol 107, pp. 214-219.

Wagstaff C., Chanasut, U., Harren, F.J.M., Laarhove, L, Thomas, B., Rogers, H.J., and Stead, A.D. (2005) Ethylene and flower longevity in Alstroemeria: relationship between tepal senescence, abscission and ethylene biosynthesis. J. Exp. Botany. Vol 56, pp. 1007-1016.

Wingler, A., von Schaewen, A., Leegood, R.C., Lea, P.J., and Quick, W.P. (1998) Regulation of leaf senescence by cytokinin, sugars, and light. Plant Physiol. Vol 166, pp. 329-335.

Plant growth regulators

Continuing the series of teach-and-learn, this 3rd post covers the use of plant growth regulators in floriculture. I just realized that my approach to studying combines what I love to do (blogging) with what I have to do (studying for my exam). It's the best of both worlds. The information for this part is taken largely from "Selecting and Using Plant Growth Regulators of Floricultural Crops" by Joyce G. Latimer, Extension Specialist in Greenhouse Crops at Virginia Tech.

Part 1-Plant growth medium
Part 2-Nutritional deficiencies
Part 4-Post-harvest longevity of flowers
Part 5-Legal protection of cultivar propagation

Plant growth regulators (PGRs) are useful tools to grow crops with the necessary characteristics for optimal marketing. The choice of PGR depends on what needs to be accomplished.
1. To reduce the growth rate of plants, improve color, and make the plant tough, use a growth retardant (B-nine, Cycocel, Bonzi)
2. To increase branching or make a bushy plant, use a chemical pincher such as Florel®
3. To initiate or synchronize flowering use a gibberellin such as Cycocel or Florel®
which causes release of ethylene in the plant.

Because PGRs are classified as pesticides, they can only be applied like someone with the appropriate training (I had to be certified to apply PGRs for a class), and only on the crops they are labeled for. When applying PGRs it is crucial not to apply an overdose, because of toxicity to the plant. Also, some plants may be more or less sensitive to a particular PGR, so you need to look that up before you start.

1. Growth retardants
These are compounds that inhibit the production of gibberellins, the plant hormone that causes cell elongation, and therefore affect the stems, and flower stalks. Shorter plants often look better in pots and are less likely to damage during shipping. Apply these PGRs early, because they may be slower in opening of flowers. B-nine and Cycocel are usually applied as early sprays (sometimes mixed together in the same tank). Bonzi can be applied later in the season as a drench (directly poured onto the moist medium).

2. Chemical pinchers
These PGRs inhibit growth of terminal shoots, causing development of lateral branches. This results in a more bushy appearance (broad as opposed to tall), and a shorter plant. They work by causing the release of ethylene inside the plant. Ethylene is a naturally occurring gaseous plant hormone that (among other things) reduces internode elongation. Be sure to apply these only if there are enough nodes on the plant to allow for lateral branching.

3. Flowering
Flowering can be enhanced by plant hormones called gibberellins, and can in some cases even be use instead of the cold temperature-requirement to break dormancy of buds for certain plants (azalea's for example). Flowers can be removed by using Florel®. This can be necessary to maintain stock plants used for vegetative propagation, or it can synchronize flowering. In the latter case, it's important to leave enough time after the treatment for flowers to develop. Peter Konjoian uses the rule of thumb of a cut-off date of mid-March for plants to bloom by Mother's Day. At least he's got his priorities straight.

There is a lot more on this topic, but these basics are all I have time for right now.

Nutrient deficiencies

This is part 2 of material I think I need to know for tomorrow's exam. I will not go into any detail with regards to fertilizer. I think I'm comfortable enough with my knowledge on that as it is.

Part 1-Plant growth medium
Part 3-Plant growth regulators
Part 4-Postharvest longevity of flowers
Part 5-Legal protection of cultivar propagation

Most of the information here is from a handout given in a class I took about a year ago, supplemented with information found on the internet.
Plant nutritionists usually divide essential nutrients for plants into macronutrients (required in larger amounts) and micronutrients (required in smaller amounts). Essential nutrients are those that are required for the plant to complete its life cycle. There is some discussion about this, because silicon (Si) is not considered an essential element, but contributes to resistance of plants against pathogens and abiotic stress. Rice is a prime example of a plant that takes up Si in large amounts, and which is much more resistant against fungal infection as a result. Si also has other effects on rice, including preventing lodging, improved yield, and such. Rodriguez and Datnoff (2005) also mention that Si improves tolerance to excess nutrients. In the discussion below, approximate concentration of the element is given as a percentage of dry weight, then which leaves show deficiency symptoms first, and then the symptoms themselves are listed. Macronutrients generally result in symptoms on older leaves first, while micronutrient deficiency symptoms first show up on young leaves. Ca-deficiency is an exception to this.

N (1.5-4%)-Older leaves to whole plant-Reduced plant growth, light green leaves, followed by general chlorosis
P (0.3-0.5%)-Older leaves and stems-Stunted growth, leaves becomes dark green, older leaves and stems may become red or purple
K (1.5-4%)-Older leaves-Marginal chlorosis becomes necrosis (sometimes only along the margins)
Ca (1%)-Young leaves-Leaf distortion and marginal chlorosis, may become marginal necrosis, causes increased susceptibility to certain plant pathogens
Mg (0.5%)-Older leaves-Interveinal chlorosis more pronounced at leaf margins, most at the leaf tip. Necrosis is possible, but less common than in K deficiency. Very common in the South in palms (see photo, credit: T.K. Broschat, click on photo for original context)

S (0.5%)-New leaves to whole plant-General chlorosis, more pronounced near the top of the plant

Fe (100 ppm)-Young leaves-Interveinal chlorosis with a netted appearance, can become general, small veins yellowing first, most common cause is high pH of the growth medium
Mn (100 ppm)-Young leaves-Interveinal chlorosis, less likely to become general than Fe-deficiency, may turn into necrotic margins and spotting, commonly caused by high medium pH or high Fe
B (50 ppm)-Young leaves-Thickened smaller leaves, shorter internodes. Leaves first become dark green, then develop chlorosis and necrosis, can result in tip dieback, and witches' broom symptoms
Zn (30 ppm)-Young leaves-Distortions, smaller leaves, short internodes (rosette appearance), mild interveinal chlorosis
Cu (15 ppm)-Young leaves-Distortions, interveinal chlorosis
Mo (5 ppm)-Young leaves-Distortions, marginal chlorosis or necrosis

Rodriguez, F.A., and Datnoff, L.E. (2005) The role of silicon in suppressing diseases. APSnet feature story February 2005. http://www.apsnet.org/online/feature/silicon/

Share my joy-Plant growth medium

The best way to learn something is to teach it. Therefore, I don't see any reason why I should be the only one learning about floriculture for my next and (hopefully) last written PhD qualifying exam. So, I will share here what I've learned today that I hope will be useful for tomorrow's exam. If you see any egregious errors please feel free to point them out to me, even if it is after my exam. Since this is likely to be a lot of material I'll divide it up into several posts. And because I'm learning at the same time I'm teaching, these posts will be a work in progress until tomorrow, and subject to change.

Disclaimer: This should not be considered an instruction manual for the culture of ornamental plants. The information presented here is most certainly incomplete, if for no other reason than that it presumes a level of basic knowledge. This is simply to complement what I think I already know with the details that I believe are important to know for my exam, that I was not (fully) aware of when I started studying this morning. Of some of these facts I was aware, and this serves to refresh my memory. Also, because I live in the South, things like cold-tolerance are of little relevance.

The five main categories I think will be important are:

1. Growth medium
-different soilless medium components
-waterholding capacity
-EC (electrical conductivity)
2. Nutritional deficiencies
3. Plant growth regulators
4. Post-harvest longevity of flowers
5. Legal protection of cultivar propagation

So, here we go.

Common soilless medium components
*Sphagnum peat moss-Consists of incompletely decayed plant material (at least 90% organic matter on a dry weight basis), usually formed in cool climates under low oxygen conditions. It typically has a very low pH, high CEC, and high water-holding capacity. It can, however, compact very easily, creating problems with the structure of the medium, and it is rather pricey.
*Rice hulls-Light weight, low CEC, cheaper than peat, high C:N ratio, decomposes easily (changing the structure in the process), microorganisms that break down the carbon will likely use up some of the N provided by fertilization, pH higher than that of peat moss.
*COIR-medium-high CEC, pH higher than that of peat moss, CEC lower than that of peat moss. Less expensive than peat, and no compaction issues.
*Yard clippings-Variable CEC (but lower than that of peat), high C:N and therefore medium structure changes because of breakdown, inconsistent availability (supply too irregular for large-scale growers), pH higher than that of peat.

Waterholding capacity
This is the volume of water in the growth medium after irrigation and drainage.

Optimum pH values for soilless medium are 5.5-6.0 according to the University of Massachusetts floriculture webpage and 6.2-6.5 for media with 20% or more soil. Individual requirements of crops vary, with Dianthus and Marigold on the high pH end, and Petunia and Salvia on the low pH end. The main problem with higher or lower pH is nutrient availability. For example, high pH results in iron deficiency, because iron becomes chemically unavailable to the plant, while low pH causes iron excess.

Electrical conductivity (EC) is an expression that measures the amount of salts in the medium. Low levels are not good, because it means that nutrients are not available to the plant. High levels are not good, because the plant would have to transpire too much water in order to take up nutrients, causing the plant to wilt (fertilizer burn). The following table is taken from Hanlon et al. (2002)

Species Type





Very High

------------------- dS/m -------------------

Woody Ornamentals


0.7 to 1.0

1.0 to 1.5

1.5 to 3.0


Bedding and Pot Plants


0.8 to 2.0

2.0 to 3.5

3.5 to 5.0


If the EC is too high, the medium can be leached out with high quality (low salt) irrigation water (EC 0.1-2.0).

That's it for growth medium.

Hanlon, E.A., McNeal, B.L., and Kidder, G. (2002) Soil and container media electrical conductivity interpretations. Circular 1092. Soil and water science department, Florida cooperative extension service, Institute of Food and Agricultural Sciences, University of Florida. http://edis.ifas.ufl.edu/SS117

Monday, February 4, 2008

Qual #5

Ugh! At first the last member of my committee did not return my e-mails to set up my last written qualifying exam. Finally I cornered him in his office this morning. And guess what? My next exam is this coming Thursday at 8:30 am. With absolutely no hint what it's going to be about other than "floriculture." This is troubling, because this member is not from my department, he is my so-called "external" committee member.

Floriculture is not my field. I'm a plant pathologist. I'm really good at making plants sick, not so good at keeping them alive. The plants in my house are (not so) living proof of that. And I have about 2 days to prepare for this exam. Well, I suppose I really cannot prepare for it. There is nothing to be done. Either I know what he asks, or I don't. It's not as if studying for the next 48 hours is going to make a damn bit of difference.

Who am I trying to fool here? I'm going to study floriculture like crazy over the next 48 hours. If anyone can think of a really important point I should know about growing flowers, this would be a good time to state so in the comments.

I'll be back after this torture is over. Or not, maybe I'll just dig a hole in the ground, lie in it, and cover myself up on 10:30 am on Thursday.

Note added: I'm not actually suicidal, and I will not be no matter what the outcome of Thursday's exam. I've faced much, much more serious hardship than failing a stupid exam. I've survived before, I will survive again, and I will be happy. Let me qualify that. I might be really pissed for failing the exam, but it will pass, and overall, I will be a happy person anyway.

Friday, February 1, 2008

Support science! Sign the petition

The Florida State Board of Education is about to adopt new science standards. Within Florida a number of school boards have passed resolutions demanding that the standards be altered in such a fashion as to allow "alternative theories" to evolution to be taught. Brandon at the blog for Florida Citizens for Science has done a fabulous job keeping track of all the board resolutions in the state and Panda's Thumb has a map showing the school boards that have passed resolutions or are in the process of doing so. What is depressing is that only 1 (!) school board has actually passed a resolution in support of science. Cheers for Brevard County.

There is now a petition up at Florida Citizens for Science for anyone to sign, which will be sent to the State Board of Education. So head on over there and stand tall in support of science!