Can I pretend the paper doesn't exist?

Well, I’ve done it.  I developed my proposal for my Master’s thesis project.  I came up with some questions, associated hypotheses, potential field methods and study organisms.  So I’m done working on my project until the May field season starts, right?

Wrong.  I’ve been keeping busy by reading any paper that might have something to do with my project.  Unfortunately, this is making me feel less and less prepared all the time.  Each paper brings up new facts, hypothesis, or field methods I hadn’t even thought about; putting the validity of my project to question. 

An old paper by Elizabeth Newell is one of those papers.  It has definitely caused some stress and worry, and has put a kink in my proposed sampling methods.  Let me summarize this paper for you, so you can have a little taste of my study without giving the details away.

Deciduous trees in winter: boring and bare? I think not!

I read through all my past blog posts yesterday in attempt to see if my writing had improved since I started BIOL 821.  I think it is getting better – it’s not poetic or anything – but my sentences are generally simple and clear.  But, my paragraphs are always too long.  I have a major problem with cutting out words, ideas, and examples that I think are absolutely necessary.  They’re not.  And see, I’m doing it again – this paragraph is clearly too long.

So for this last non-research post, I’m going to talk about what deciduous trees do in winter, with a main goal of writing short, concise paragraphs (this is a good start!).

Having sex two times in a row is exhausting (for plants too!)

For humans, having sex once – let alone twice – a day is tiring.  Although we may need a nap afterwards to recoup, taking the time and energy to have sex is worth it!  Besides the obvious feel-good perks, sex can actually improve our health by relieving stress, boosting our immune system, burning calories, and helping us sleep better.

Everyone gets tired after sex - especially if
 you 'do it' twice in a row!
Image from: http://www.lifedynamix.com/


However, sex may be far more exhausting and less rewarding in plants.  Unlike humans, studies have suggested that plants are not capable of consecutive sex sessions and sex can even decrease their wellbeing; investment in reproduction may result in losses to vegetative growth and maintenance. 

 

Fittingly, Bernett, Laemmerzhal, and Rockwood (2009) set out to test how draining sex actually is for herbaceous plants.  They used a large population of bloodroot (Sanguinaria canadensis), a rhizomatous, perennial herb.  The population was located in a 100 year old temperate deciduous forest in Virginia, within which they set up a 50 x 100m sampling quadrat.



In spring 2003, Bernett et al. tagged all flowering bloodroot individuals within the quadrat with yellow flags.  After flowering was complete, they returned to count the fruits and seeds produced by the tagged individuals.  They also measured the area of the solitary leaf produced by each plant.



Flowering individuals of a bloodroot
(Sanguinaria canadensis) population

In spring 2004, Bernett et al. returned to the population for more tagging: individuals that only flowered in 2003 kept their original yellow tags, individuals that flowered in 2003 and 2004 were retagged with orange flags, and individuals that only flowered in 2004 were tagged with pink flags.  For each flowering individual, the same counts and measurements were recorded as in 2003.

 

Surprisingly, there was a dramatic reproductive and vegetative difference between plants that flowered in 2004 only versus those that flowered in both 2003 and 2004.  Significantly fewer plants flowered in both years than in 2004 only.  Plus, plants that only flowered in 2004 produced significantly more fruits, more seeds, and 20% larger leaves than those plants that flowered consecutively.



Figure 1 from Bernett et al. demonstrating the signficatntly reduced
leaf area in plants that reproduced consecutively

The results clearly demonstrate that each reproduction event is tiring and expensive – most plants can't even flower two years in a row.  Plus, plants that did flower consecutively had to steal vegetative resources to do so, and were far less capable of producing offspring.

Although a ‘roll in the hay’ (or two) for humans leaves us out of breath for a few hours post-action, we typically feel good afterwards and embrace many unexpected health benefits.  For many plants, however, sex can leave them out of breath for a year or more, decreasing offspring output and vegetative size. 

Consecutive sex in plants, then, hardly seems worth it.  Successive reproduction reduces future plant livelihood by reducing leaf size; smaller leaves result in decreased surface area required for light capture and decreased photosynthetic cells responsible for energy production.  Plus, producing flowers in the second reproductive year is often energetically wasteful; these flowers often fail to produce fruits or seed.

Or is it worth it after all?  Consecutive reproduction events – draining or not – help to evolve the species more rapidly; more reproduction events result in more recombination, which leads to more potential for new genes.  This will ensure that bloodroot individuals are more environmentally adaptive on our ever-changing planet.

Sources:

http://www.webmd.com/sex-relationships/features/10-surprising-health-benefits-of-sex?page=3

http://www.lifedynamix.com/articles/Anti-Aging/Sleep_Program.html
Bernett CC, Laemmerzhal A, Rockwood LL (2009) Reduction in reproductive output and leaf size in Sanguinaria canadensis as a cost of reproduction. Journal of the Torrey Botanical Society, 136:4, 457-464.

AFPs - A bit of ecology, physiology, and biochemistry



My deer watch on a chilly Friday
morning

On Friday morning, I was freezing to death standing on my deer watch.  The sun hadn’t come up yet, and wind was blowing right in my face.  The freshly fallen snow was soaking my boots and pants, and sent extra chills up my spine.  These freezing temperatures, howling wind, and inches of snow surely meant death to all of the once vibrant and colourful herbs.  But beneath the accumulating snow, there were a few green survivors trying to hold on.  How were they not frozen when I – dressed in layers of long underwear, jackets, and gloves – clearly was?



In most herbaceous plants, ice crystals begin to form within the liquid-filled intercellular spaces of cells when winter comes.  These crystals continue to expand, bursting and killing the cell, and eventually the whole herbaceous plant.  However, some plants – along with animals and insects – produce antifreeze proteins (AFPs) in their bodies to adapt to cold environments.  Reduced day length and cold trigger production of AFPs in many plants to make them freeze tolerant (capable of tolerating some cold) or freeze avoidant (avoiding freezing altogether). 

A potential positive of climate change

Researchers have warned that global warming will take a toll on our planet, especially our plant populations and communities.  High inputs of carbon dioxide into the atmosphere from vehicles, manufacturing, and industry will surely affect the distribution, ecology, and adaptation mechanisms of plants across the globe both directly and indirectly. 

The question is: how will plants be affected?  Little research has been done to try to quantify the impacts that excess carbon dioxide will have on various communities of plants, although scientists are certain that it will be negative.  However, the following study shows that increases in CO2 could actually be a good thing for forest recovery and succession.