When to Water: a Plant Physiological Approach
Monday, February 6, 2017
Week 1
Hello, everyone. Welcome back to WTW. This week, I would like to explain the vascular systems of plants. I played around with a couple of ideas of how to make this less dry including writing in emojis (I could only get this far: 🌨🌳💧🍃. Bonus points to anyone who writes his or her comment with emojis), but I figured the best course of action was to go straight ahead.
Plants need sugars to store energy and to build structures. Plants get sugars by making them in the process of photosynthesis, which requires carbon dioxide and water. To take in carbon dioxide for photosynthesis, plants open pores called stomata. However, when plants open these pores, water transpires (escapes) the plant from these very pores. This, along with the evaporation of water from the leaves, depressurized the leaves, which causes some water to fill its place. Water is cohesive, meaning it sticks together. Thus, the water moving up to replace the evaporated and transpired water drags with it more water through the xylem (a specific type of plant tissue that water moves through). This dragging continues all the way down to the roots, which is where the plant gets the vast majority of its water. Of course, there are other factors and we can pretty far in the weeds (or any vascular plant for that matter), but that seems to be enough for one week.
So what does it mean when there is not enough water in the soil to replenish the water lost through evaporation and transpiration (when a plant is water-stressed)? Microscopically speaking, a lot, but since I am working in a plant physiology lab, let us focus on more macroscopic things. Growth of the plant decreases. Yield also lessens. The droopiness and brownness increases. However, those are all just symptoms. How do we quantify how water stressed a plant is? To find out, you will have to come back next week to WTW (or Google around and read some papers, which I would also encourage to anyone who might be intrested).
P.S.
After a couple of days of doing the senior project at AgriSense, I realized that there are some logistical challenges to completing my senior project at AgriSense, so while AgriSense is still plugging along, I have switched locations to the Desert Botanical Garden. I have been performing research there since 2015, so it was an easy transition. There, I am working under the direct supervision of Dan Kopke. Of course, if anything of note happens at AgrisSense, I will share it here.
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First of all, thank you for explaining the connection between water in the plant and water in the soil! I also found it interesting when you stated the "symptoms" of a water-stressed plant. I had never thought of these as symptoms before, but had just taken them as fact: plants droop when dry. I'm looking forward to learning how you quantify these examinations, which is another thing I hadn't thought of before (or even thought was possible!).
ReplyDeleteThanks Ziba. I'm glad you found this post interesting.
DeleteThis is very interesting. I can see the advantage you have with the concept of water stress and its importance here in Arizona. I'm very excited to see your progress in the weeks to come! ��
ReplyDeleteThanks for reading, Tara
DeleteHey Brian, I found this week's blog post extremely ravishing. What do you mean when you say that yield also lessens, when you were referring to the "symptoms" of plants? Believe it or not, iv'e actually wondered how scientists quantify how water stressed a plant is. P.S. Bonus points!!!!!! ��������
ReplyDeleteThanks for the question, Joey. Yield is simply how much fruit (or whatever thing is being harvested) is produced by the plant. When I wrote yield decreases with water stress, I am saying the size and number of the useful parts of the plant lessen.
DeleteHey Brian,
ReplyDeleteThis week's post was just as entertaining and informative as last's. The concepts of water-stressed and plant symptoms were especially interesting to me. I am excited to see what you learn next and can't wait for next week's post.
Nishant, I am happy to read that you enjoyed the post. I'm glad to know which parts you enjoyed. I'll try to come back to them in later posts.
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ReplyDeleteHi Brian,
ReplyDeleteI was interested to read about the symptoms a plant can experience when it is water-stressed, and about a plant's relationship with water, its roots, and soil. This post was quite interesting and I'm excited to read more and follow along with your project!
Ang, thanks for you comment. I'm happy you enjoyed the post. I'll definitely be talking more about symptoms (probably week 3).
DeleteHi Brian,
ReplyDeleteYour description of the vascular system of plants was very detailed yet concise. However, what do you mean by "there are other factors and we can pretty far in the weeds"? (could be a typo or maybe i'm just being dumb) Im interested to read more about your research and findings. Can't wait for next
week!
Akash Anickode
Hi, Akash. Primarily, I was going for a bad pun. I was also trying to say that, for the sake of simplicity, I left out many factors that cause the movement of water in plants.
DeleteThat's some pretty informative stuff. What happens if you overwater a plant? Overwatered plants also get droopy, but are these two cases similar to each other?
ReplyDeleteEric, at WTW the stuff is always informative 😁. And here's some more information. Plants can never have too much water, but that can have too little oxygen. If there is so much water in soil, that the soil becomes anoxic (it has no oxygen in it), which hurts the plant and the helpful bacteria living in its roots. This is what causes the plant to droop. Excellent question! I think I might do a post on soil later because there seems to be (relatively) lots of interest.
DeleteVery interesting and informative. Will the implementation of you research be difficult?
ReplyDeleteHi, Manu. Time consuming more than anything. The procedures I am using are well laid out in several papers. The sheer number of leaves I will be working with is the largest challenge.
DeleteI never knew much about plants before, but your project seems very interesting. How is working at the Botanical Gardens like? As an Arizonan, water conservation must mean a lot to you. I look forward to next week.
ReplyDeleteSaaketh, the DBG is a great job. I work whenever I want and however much I want. It is gorgeous (more on that in next week's post). Plus, I really enjoy doing the labwork.
DeleteThis was very interesting! I had no idea how water evaporating from the stomata drew in water from the roots!
ReplyDelete