Questions tagged [plant-physiology]

Study of the normal functioning of plants and plant cells

106 questions with no upvoted or accepted answers
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184 views

How many cells are there in the apical meristematic tissue?

How many cells are there in the apical meristematic tissue? Looking at this picture... , I would tend to think that there are few hundreds cells in the meristem tissue. But I guess this is a picture ...
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4answers
1k views

Stomata during night (respiration)

How does carbon dioxide from respiration diffuse out of the leaf during the night? Do stomata close completely during night?
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510 views

Do plants have cellulases?

I can't seem to find the answer to this. Not even Wikipedia could help- it mentioned bacteria and fungi that have cellulases but not plants. Using my own reasoning, I would think that On the one ...
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1k views

Pits and Pores in Vascular Tissue

What purpose is served by the pits and pores in xylem and phloem cells? I cant find what purpose that these components serve in the vascular tissues in plants
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26 views

How does a heat-ratio sap flow sensor work and how invasive is it?

The Gizmodo article Undead Tree Stump Is Being Kept Alive by Neighboring Trees says: Leuzinger and Bader stumbled upon the stump while out for a hike. The woody stub caught their eye because callus ...
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190 views

Regulation of LBD33 genes Arabidopsis. If LBD 33 gene is up-regulated by auxin then why does expression decrease when increasing auxin concentration?

I have a question regarding the regulation of lateral boundary domain genes in Arabidopsis (specifically LBD33). I am an undergraduate student trying to understand the results of a lab where I measure ...
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48 views

What is a good approximate functional form for an equation relating plant growth to sunlight?

Question is in the title. I've got daily measurements of daily mean shortwave radiation at the surface, and annual measurements of plant growth (some measure, be it height or biomass or something). ...
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69 views

What amount of light energy is required to produce one O2 molecule? How about one molecule of NADPH?

I know that for each O2 molecule, a total of 8 photons are required (4 per photosystem). Would the amount of light energy required be E=hc/wavelength using 680 and 700? Or would the energy from the ...
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107 views

Can photorespiration do any good?

When CO2-levels are to low plants start to photorespirate instead of photosynthesise. This cost them losses in energy, and adds CO2 to the atmosphere instead of O2. I wonder if the photorespiration ...
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159 views

How did fig tree take root in trunk of palm tree?

Please see pictures below. I never saw anything like this. Do the roots of the fig tree penetrate the trunk of the palm tree? Is there a symbiotic relationship between the two?
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25 views

Why do certain ferns have roughened spore surface?

Ferns such as Anemia phyllitidis, Blotiella lindeniana, Ctenitis hirta, Cystopterix fragilis, Hemionitis palmata and many others have roughened splity spore surface. I ask, why is it evolutionary so?...
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177 views

Why does a broad-leaved evergreen (Mahonia aquifolium) has red leaves?

To my knowledge, oregon grape (Mahonia aquifolium) is purportedly an evergreen shrub? Deciduous broadleaf plants lose their leaves in autumn usually and before that as the leaves die they oxidize and ...
3
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1answer
251 views

How to measure the biomass of hydroponic plants in netpot/rockwool DWC system?

I'm doing an experiment with 4 kale plants, each in their own small deep water culture (DWC) system. Each plant was transplanted in rockwool with netpots and clay pebbles. But I need to periodically ...
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306 views

Can Galactose be synthesized with photosynthesis?

I know that galactose can be found in sugar beets and some gums so I thought plants could synthesize galactose but in my book the answer to the question "Which of these can be synthesized with ...
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725 views

What metabolic processes do dormant and ungerminated seeds carry out?

What metabolic processes does a dormant embryo in a seed carry out? Seeds will not germinate, either because of a lack of favourable conditions, seed hibernation, or because of a genetically pre-...
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416 views

Is there a standard definition for plant “maturity”?

Is there a species-agnostic metric for identifying plant maturity? There seems to be plenty of literature defining life-history stages for specific crops, but it is not clear if there is a generic ...
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21 views

A single leaf in a very strange air current / wind?

Here is my eight years old movie where I have pictured a single leaf moving in a very weird way: https://www.youtube.com/watch?v=sCjvgdfNCjU Can someone explain me what is depicted in this movie (...
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39 views

Has anyone confirmed Darwin's theory that nectar began as something “injurious” to sap?

In "Origin of Species", Darwin says (I have added bold for emphasis): Certain plants excrete sweet juice, apparently for the sake of eliminating something injurious from the sap: this is effected,...
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170 views

How does heat stress kill plants?

It is known that many plants typically die when exposed to temperatures of 40 to 50°C (I believe, these figures relate to exposure times of ~1–2 hours). When a plant is heated, what is the mode of ...
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24 views

Why does the iron content differ in different species on seeds?

Iron can be affected by pH of the soil but why does each species actually have a different iron content. What causes it? What genes cause it?
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31 views

Why don't acacia trees prefer increasing tannin levels in their leaves rather than leaving them high?

According to this article, the Acacia tree has a chemical defence system which leads to the release of ethylene in the surroundings when a herbivore grazes on it. This leads to an increase in tannin ...
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12 views

Fixing plant leaf tissue for tensile tests

I'm a new master's student in mechanical engineering, and I'm researching crop biomechanics. We need to do some tensile tests on samples of corn stalk sheath, which involves securely and evenly ...
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123 views

Does blue light cause stomata to open or close?

In my biology lecture notes, it says that blue light causes stomata to close. But thinking about it logically, since plants absorb a high percentage of blue light compared to light at other ...
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0answers
163 views

Why do plants produce and store both amylose and amylopectin?

Since both forms of starch has its primary purpose of storing glucose and hence releasing energy, why are there 2 variations of this sugar? Is it possible for an organism to contain/depend only on 1 ...
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0answers
232 views

Are there special pairs present in the RC of both photosystem I and photosystem II?

I am confused regarding the existence of special pair (primarily regarding PS2). Do both, P680 and P700 have special pair? I have checked various sources online and have come across conflicting ...
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74 views

Why does abnormal mitosis takes place in the cells of tapetum?

I know that the tapetal cells present in the anther are binucleate. I also know this means that after karyokinesis the cell does not divide itself and instead form a syncytium. This occurs due to ...
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134 views

Why do basil leaves turn black?

I notice that when I buy basil it is fresh and green in the store, but when I take it home it wilts and turns black within 24 hours. Why does it do this?
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399 views

“CO2 is plant food” - What is the actual effect of increased CO2 on plant growth?

A frequent talking point by global warming deniers is that CO2 in the atmosphere is actually beneficial because "CO2 is plant food". I'm a non biologist trying to figure out under what circumstances ...
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29 views

What is a rough estimate of CO₂ saturation for high-yield or high growth rate plants?

Naturally, plants have individual photosynthesis capacities, but it would still be interesting to get a general picture of CO2 saturation levels for some common cultures. Where lies the optimal yield, ...
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487 views

Is there a plant particularly suitable for absorbing Hydrogen Sulfide

I live in an area with some open sewers and in the morning I can usually can smell the gas inside my house. There are many plants like snake plant which improve indoor air quality but I was ...
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0answers
40 views

Which biosynthetic pathways take place in the plastid and were are they located?

I know that the isoprenoid, jasmonate, glucosinolate, fatty acids, chlorophyll, starch, and aromatic amino acid syntheses are located in the plastid. But I don't know if they are located in the ...
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59 views

Rosemary room temperature at winter

I consistently read in non-scientific resources that I have to put my rosemary to low temperature (about 10°C) in winter (unless I don't want it to freeze). I googled, but I fail to find a scientific ...
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2k views

Is it possible to simulate the effects of high altitudes for plants?

Note- I considered asking this on gardening.stackexchange.com but i believe it is better suited for this site since it deals with more complicated material. As I understand it, certain plants (...
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18 views

Are Hsp70 proteins only activated in response to heat shock?

Hsp70 proteins are chaperones that assist in protein folding in my plant physiology textbook it says the Hsp70 proteins were discovered by inducing heat shock. But do they only work in response to ...
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31 views

Spatial sequence of autumn leave colouring: top to bottom

Leave colours on trees seem to vary on the same tree from top to bottom. Leaves higher up are already further ahead in the shedding process. What's the reason for this tempero-spatial gradient?
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33 views

Are there any evolutionary reasons for the different tree shapes? If so, What are they?

So we know there are a thousand types of trees with different shapes. We have Columnar shaped trees: Pyramidal or Conical shaped trees: Weeping shaped trees: And we also have Round, Vased, Open-...
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21 views

Chemical inhibition of fertilization in plants

Are there any chemical compounds that inhibit fertilization in plants after gametogenesis? Simply put, I am talking about spermicide or emergency contraception for plants. Specifically, I am ...
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0answers
22 views

Near-zero water loss in a closed hydroponics system?

I know there are a lot of factors that would impact this... Plant type. Plant neediness (i.e., even sibling plants will possess different needs, defects, etc). Automation efficiency. Water & ...
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0answers
11 views

How does Liebig's law affect the growth of specific characteristics on a plant

I am familiar with the law of minimum, that is that the growth of the plant is dependent on the least available nutrient/resource. I visited a farm in which they purposefully shaded tabaco plants to ...
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22 views

What genes in a plant determine whether a stem is erect or climbing?

I was randomly reading this Wiki article on Jasmine and this question crossed my mind after reading the following lines: Jasmine can be either deciduous (leaves falling in autumn) or evergreen (...
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0answers
74 views

What makes the flowers glow?

I had learnt in a plant biology course that, all the flowers are actually originating from leaves, with several mutations. I wonder what makes a flower sparkly like this. Photos belong to a ...
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0answers
23 views

Biological Nitrogen Fixation

I just studied Biological Nitrogen Fixation and saw it's reaction but i do not understand why there is 8 electrons and 8 protons are involved and Hydrogen molecule is formed side by side along with ...
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217 views

What is difference between light harvesting complex , reaction centre and photosystem

my book says light harvesting Complex are made up of hundred of pigment molecule bound to protein. Is photosystem has all the pigment (except one molecule of chlorophyll A )forming light harvesting ...
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55 views

Fruiting of trees — environmental stimuli and biochemical cascades

My question concerns fruiting of trees in general. However, I live in a tropical country (Philippines) where mango trees are ubiquitous, so I'll use it in stating my question. The question is about >...
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0answers
56 views

How is the role of ethylene in ripening demonstrated in biology (or agriculture) education?

I want to know what are some typical experiments performed in the course of biology education (or possibly in applied biology education e.g. agricutlure education) to prove to the students (or have ...
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66 views

Could higher carbon dioxide levels be beneficial to plants?

C4 plants take ATP-expensive routes to ensure photorespiration does not occur. They minimise oxygen concentration in cells where the Krebs cycle occurs and cart carbon dioxide into these same cells. ...
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34 views

Rubisco and Nitrogen Shortage Condition

Suppose a plant sprouted when $t=0$ and died when $t=T$. Let $t_*$ be the time when the plant shifts the resources usage to maximize its reproductive organ. In the case of nitrogen shortage during ...
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10 views

Measure Water-Use Efficiency without using carbon isotope fractionation?

I read "Measurements of delta (C-13) in C3 species may usefully contribute to the selection for transpiration efficiency." I think the device to measure carbon isotope fractionation is very expensive. ...
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100 views

Effect of high temperatures on plant stomata

My biology textbook states that stomatal closure occurs at high temperatures to avoid water loss. Another stackexchange thread I can find (What is the effect of temperature and carbon dioxide on the ...
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0answers
657 views

How many photons are used to make one glucose?

This was a question in a test. The options were (1) 8 (2) 16 (3) 24 (4) 48 My answer is 30 which was not in options. Given answer was 48. 12 NADPH 18 ATP for one glucose 12 NADPH and ATP ...