Today's meeting and notes for next Friday--READ ME CAREFULLY, please

[Susan Mazer]

Hi Leah,

Today's meeting with the students went well, and they all had great observations and realizations about our work together; I'm sending this to you and to the entire group so that they can get a re-cap of what we covered.  EVERYONE IS EXPECTED TO READ THIS EMAIL CAREFULLY IN PREPARATION FOR NEXT FRIDAY'S 3:00 MEETING IN 4307 LSB.  

I described the three major projects that are next in line, after we've completed the greenhouse experiment.  Projects 1 and 2 will be initiated as necessary when it's too hot to be in the greenhouse, but everyone understands the important to complete the pollinations and to prepare the seeds for the field experiment.  I spoke with Hannah about her working on weighing the seeds of each maternal family (e.g., 30 seeds per family) to obtain the mean seed weights of all the families that we'll raise in the field.  I'm not sure that there's enough time to weigh each group of 10 seeds (each microcentrifuge tube) separately.  

Bridget alerted everyone about how to indicate on the data sheet in the greenhouse whether a maternal family has been sufficiently pollinated so that students will move on to pollinate families that still need to be pollinated rather than over-pollinating ones that are "done".  Students who work in the greenhouse next week should be sure that they learn from Bridget or from another students how to do this!

The three projects I described were as follows (first, ask one student to remind the newcomers of all four taxa and whether each is selfing or outcrossing):

Project 1. The pollen tube competition study.  This is being worked on by Brandon, Arrash, Alex, and possibly Lindsay Nord.  The goal here is to complete the counts of pollen deposition and pollen tubes in the stigma/styles collected in 2010.  With these data, we can determine whether the strength of pollen competition based on pollen deposition on the stigma (more pollen grains deposited on stigmas than there are ovules) is similar to pollen competition based on the counts of pollen tubes either at the stigma-style junction or at the base of the style.  

Brandon already completed the counts of 400 styles from 2009, and Lindsay Halford counted the grains and tubes from 200 styles from 2010.  There are 450 more stigma/styles to process from 2010.  Brandon is overseeing the training of Arrash (beginning at 6:00 pm on Monday).

The students understand that we are interested in figuring out whether the ratio of pollen tubes to the number of ovules in the ovary indicates strong pollen tube competition for access to ovules in Cxx and Cu.  I explained that we may also detect evidence explaining why Cxx does not have faster pollen tubes than Cxp, while Cu does have faster pollen tubes than Ce. That is, perhaps there is actually less pollen tube competition in Cxx (the pollen supplementation experiments notwithstanding).

Brandon, Arrash, Katie, and Jennifer have agreed to explain this project to you and to the students who couldn't make it to today's meeting.

Project 2. The study of the relationship between P:O and flowering date in the greenhouse populations of Cxx and Cu.  On a bivariate graph of P:O vs. Flowering Date, I illustrated that the selfing TAXA have lower P:O ratios and early flowering than the outcrossing TAXA.  Then I explained that the analysis of the greenhouse buds will allow us to test two hypotheses within the outcrossers, both addressing the question:  Does the genetic correlation within species mirror the genetic differences between sister taxa?

a) Do maternal families with low P:O ratios flower earlier than maternal families with high P:O ratios.  

b) Does the Early Flowering selection line have a lower P:O ratio than the Control lines?  

Bridget, Jackie, Hannah, and Sonya have agreed to explain this project, and they should be able to illustrate and to explain the figures that I used during the meeting. Be sure to have them start by defining how we measure the pollen:ovule ratio!

Project 3 (to be started after the greenhouse flower buds are completed). The study of the relationship between P:O and physiological rates (photosynthesis and transpiration) in field populations of Cxx and Cu.  On a bivariate graph of P:O vs. Physiological rate, I illustrated that the selfing TAXA have lower P:O ratios and faster physiological rates than the outcrossing TAXA.  Then I explained that the analysis of the field-collected buds will allow us to test one hypothesis within the outcrossers and within the selfers.

a) Do individuals with faster physiological rates also have lower P:O ratios?  Again, does the correlation within species mirror the genetic differences between sister taxa?

Tammy, Vaishnavy, Robin, Graham, Danny, and Steve have agreed to explain this project, and they should be able to illustrate and to explain the figures that I used during the meeting.

I wish I could be there!  Let me know if you have any questions.....

Best,

Susan

Susan Mazer

Professor of Ecology & Evolutionary Biology

University of California, Santa Barbara

Santa Barbara, CA 93106

cell phone: 805-729-3980

office: 805-893-8011

FAX: 805-893-4724

email: ma...@lifesci.ucsb.edu

http://www.lifesci.ucsb.edu/eemb/faculty/mazer/index.html