Questions tagged [plant-physiology]
Study of the normal functioning of plants and plant cells
126
questions with no upvoted or accepted answers
11
votes
1
answer
119
views
What actually kills a plant that requires winter dormancy if it is kept indoors all year?
In bonsai practice, beginners will commonly purchase a juniper (often Juniperus procumbens 'Nana'), which is an outdoor tree, and keep it inside all year. The tree invariably dies. It is commonly ...
- 219
5
votes
0
answers
1k
views
Explanation of the results of Warburg's Flashing Light experiment?
Between 1919 and 1920† Warburg obtained a higher rate of photosynthesis in Chlorella, exposed to rapid alternating periods of light and darkness, than when exposed to constant illumination. I would ...
- 392
4
votes
0
answers
61
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).
...
- 141
4
votes
0
answers
2k
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
- 41
4
votes
0
answers
820
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-...
- 4,669
3
votes
0
answers
82
views
Why do sieve elements need to be alive
I am studying high school biology and I got these two pieces of information in khan academy and wikipedia:
Sieve elements in phloem are living cells because the translocation includes active ...
- 31
3
votes
0
answers
34
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 ...
- 5,094
3
votes
0
answers
203
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 ...
- 221
3
votes
0
answers
97
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 ...
- 125
3
votes
0
answers
128
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 ...
- 193
3
votes
0
answers
316
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?
- 193
3
votes
0
answers
29
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?...
- 151
3
votes
0
answers
392
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 ...
- 123
3
votes
0
answers
451
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 ...
- 161
3
votes
0
answers
428
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 ...
- 696
2
votes
0
answers
22
views
Is there always a leaf(s) attatched to an auxillary bud?
I'm trying to create a 3D functional-structural plant model and I need to establish some axioms.
Is it guaranteed or extremely likely that where auxiliary bud forms there's a leaf(s) attached? That's ...
- 21
2
votes
0
answers
29
views
How much sunlight is required for photosynthesis to peak?
I've read that photosynthesis peaks at some point over light intensities https://en.wikipedia.org/wiki/PI_curve According to https://www.bbc.co.uk/bitesize/guides/z9pjrwx/revision/5 suggests
At very ...
- 121
2
votes
0
answers
35
views
What causes the distinct color change in matured leaves in some plants?
Maybe that color change is caused by lower chlorophyll concentration in younger leaves' cells, or chlorophyll a to b ratio differs between younger and older leaves. All I could find is that the ...
- 257
2
votes
0
answers
97
views
Regarding secondary growth in dicotyledonous angiosperms
I had read that (and as this image shows) the secondary and primary phloem eventually get crushed due to the repeated division of cells forming the secondary xylem, during secondary growth in ...
- 215
2
votes
0
answers
38
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?
- 149
2
votes
0
answers
27
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 (...
- 313
2
votes
0
answers
48
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,...
- 383
2
votes
0
answers
393
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 ...
- 21
2
votes
0
answers
25
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?
- 21
2
votes
0
answers
216
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 ...
- 3,667
2
votes
0
answers
14
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 ...
- 21
2
votes
0
answers
118
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 ...
2
votes
0
answers
277
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 ...
- 1,257
2
votes
0
answers
245
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 ...
2
votes
0
answers
79
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 ...
2
votes
0
answers
212
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?
- 2,290
2
votes
0
answers
36
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, ...
2
votes
0
answers
514
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 ...
- 21
2
votes
0
answers
42
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 ...
- 174
2
votes
0
answers
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 ...
- 4,460
2
votes
0
answers
3k
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 (...
- 203
1
vote
0
answers
18
views
Do Glycosides in plant seeds serve some other function than protecting the seeds?
Many plants have toxins like glycosides in the seeds and I think other parts of the plant and the accepted reason for this I believe is to discourage animals that ingest the seeds from digesting ...
- 293
1
vote
0
answers
38
views
Is a plant's own compost better for the plant?
Does it make a difference if a plant is composted and used for its own compost ?
Meaning, let's say there is a plant "X" (example Cucumber)
Would it grow better if the compost was made from ...
1
vote
0
answers
9
views
Does lower stomatal conductance of water influenced by elevated CO2 decrease overall evapotranspiration?
From what I understand, elevated CO2 levels decrease the stomatal conductance of water in plants. What I remember from irrigation sciences, higher temperatures should be more demanding on ...
- 155
1
vote
0
answers
35
views
Photolysis of water
Photolysis of water releases $\text{O}_2$, $\text{H}^+$ ions and $\text{e}^-$.
$\text{Mn}$ in the $\text{O}_2$ evolving complex also produces $\text{e}^-$.
What provides $\text{e}^-$ to P680:$\text{Mn}...
1
vote
0
answers
297
views
Calculation of solute, pressure and water potential
What would be the water potential (Ψw), solute potential (Ψs) and pressure potential (Ψp) at equilibrium when a cell with Ψs= – 0.7 MPa and Ψp= 0.7 MPa is placed in a solution with Ψs= – 0.5 MPa? (...
1
vote
0
answers
31
views
How long can zooxanthellae survive on their own, after being expelled from coral after a bleaching event?
So many sites (and books and journals and such) discuss how long different types of coral can survive without their dinoflagellate algae (zooxanthellae), but...
How long can the poor little symbiotic ...
- 497
1
vote
0
answers
26
views
Does Ethylene Triple response provide any advantage to the Arabidopsis thaliana Etiloated seedling,?
As ethylene has a triple response effect on Arabidopsis thaliana Etiloated seedling-
1 Shortening and thickening of Hypocotyl
2 Exaggerated apical hook
3 Short root
According to this site
Ethylene ...
1
vote
0
answers
139
views
The reason behind red drop effect
I was reading about Emersion effect on Wikepedia, I was not able to correlate our current knowledge of photosynthesis with this effect,
First red drop effect
When Emerson exposed green plants to ...
1
vote
0
answers
63
views
Can Monsanto's (in)famous hybrid seed crops be cloned/grafted? If not, is there a technical or legal reason?
I understand that the seeds of a crop made from modern-day super hybrids will not, usually, produce the same quality plants in the next generation. Therefore, farmers have to buy new hybrid seeds each ...
- 497
1
vote
0
answers
15
views
How does a diploid sporophyte form in non-recurrent apomixis?
I came across this definition of non-recurrent apomixis which occurs in angiosperms-
In non-recurrent apomixis, both the egg-cell and embryo are haploid and embryo is developed directly from an egg-...
- 215
1
vote
0
answers
26
views
Why certain COGs appears more often in Humans Bacteria but not in plants Bacteria
I'm doing a Bioinformatic project from the university where I got a DB of COGS from Human & Plants Bacteria genomes and I need to find distinguishing sets in this DB and explain the biological ...
- 111
1
vote
0
answers
9
views
Where can I find a cannabinoids profile of hemp strains?
For my web article, I need to find out the content of individual cannabinoids in hemp strains, specifically for Kompolti, Carmagnola and Purple Haze. I mean the content of all the components, not just ...
- 11
1
vote
0
answers
17
views
Is it possible to accelerate active transport in plant vascular system using some electronic method?
I am from electronics background and got an understanding that electrical current affect plant growth. Based on this phenomenon, I got an idea but before I formulate my hypothesis and start ...
- 111
1
vote
0
answers
23
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 ...
- 221