Questions tagged [plant-physiology]

Study of the normal functioning of plants and plant cells

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15 views

Emerson's 2nd effect/ Emerson's enhancement effect and evidence of existence of 2 photosystems

(https://i.stack.imgur.com/Qbai6.jpg) https://en.m.wikipedia.org/wiki/Emerson_effect I can't understand why is there a need of 2 photosystems (2 interconnected pigment systems) to explain Emerson's ...
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How does wall pressure oppose osmotic pressure?

This question is based on the equation: Diffusion Pressure Deficit= Osmotic Pressure - Wall pressure I know that wall pressure is directed towards the protoplasm. I need to make sure if osmotic ...
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If a plant root is under the influence of both gravity and a source of water which direction will it grow?

Which stimulus is the strongest? Which stimulus will have most effect? What I mean is if I take a plant and plant it in soil such that the soil has more water content and minerals in upper layers ....
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Osmotic pressure

Osmotic pressure is defined as: The pressure that would have to be applied to a pure solvent to prevent it from passing into a given solution by osmosis. And yet water moves from low osmotic ...
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Relation between osmotic pressure and pressure potential? [closed]

What is the difference between osmotic pressure and pressure potential ?
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Can any animals photosynthesize?

Plants and animals have the following distinct properties: Plants live from solar energy by photosynthesis, they use solar energy to make sugar and oxygen out of carbon dioxide, which gives them ...
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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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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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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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5k views

Blue light in a fridge. Is it really beneficial or just marketing?

Recently while visiting a shop with electronics I saw a fridge with a huge advertisment sticker going more or less like this: There's blue light source in this fridge so there will be less bacteria ...
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Are agave plants perennial?

If I were to harvest an agave plant for its nectar, would it kill the plant? I have watched videos of the process and it seems quite invasive.
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1k views

Why does spiral or annular thickening occur in water conducting plant vessels?

From what I behold, spiral and annular thickening of xylem and trachied cell walls leaves a lot of not thickened regions of cell wall. Lignin is the material which prevents water from escaping these ...
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Why is amylose insoluble in water?

In a handout the following is stated: Amylose is insoluble in water, therefore a good storage compound e.g. in stroma of chloroplasts This is with regard to the chemical structure of the molecule. ...
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Is Valerian extract a diuretic or an antidiuretic?

I am trying to determine if valepotriates (valerian extract) is a diuretic or an antidiuretic. Some individuals take valerian as an herbal supplement for anxiety disorders. Some individuals claim that ...
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What's the (or some of the) minimum(s) amount of atmospheric carbon dioxide needed by plants?

We currently have a problem of increasing $\ce{CO2}$ in the atmosphere. But assuming we find a way to carbon sink it, what is the minimum $\ce{CO2}$ we need to leave in the atmosphere to provide a ...
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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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Why do plants do Photosynthesis and then Aerobic Respiration? [duplicate]

Plants do Photosynthesis in order to convert sunlight energy into chemical energy. They first store energy in ATP + NADPH and then use those two compounds in order to create Glyceraldehyde 3-phosphate ...
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136 views

Why does water stress lead to alkalinity of xylem sap in plants?

I was reading this book: Plant Physiology and Development, Sixth Edition by Lincoln Taiz, Eduardo Zeiger, Ian M. Møller, and Angus Murphy when this doubt came to my mind. Abscisic acid, the stress ...
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283 views

Viruses selected by evolution

I had a conversation with a family member who is a bio-computer-scientist and he talked to me about what his colleagues (biologist) are doing and I feel confused about it. They work in Chile and are ...
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How long will a vegetable live for after being harvested?

I understand this might depend on the types of vegetables, but is there an average or studied specifics? Does it die immediately? Is there a way to precisely diagnose death in plants? If so, what are ...
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26 views

Is it possible to grow a part of a plant independent of the rest?

Is it possible, using modern knowledge of biochemistry and synthetic biology, to grow a tomato without growing the rest of the tomato plant? As an academic exercise, with full knowledge of the fact ...
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1answer
138 views

Effects of tobacco smoke on plant health

We know that tobacco smoking is associated with a wide range of negative health effects in humans, which holds for active smoking, second hand smoking and probably even third hand smoking. What are ...
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1answer
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How is C4 pathway more water efficient than C3 pathway in photosynthesis?

In the C3 pathway: 1 H2O molecule is required for the fixation of 1 CO2 molecule. In the C4 pathway: The only H2O molecule used is in the calvin cycle, so 1 H2O molecule required for fixation of 1 ...
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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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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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How does coconut water solidify into hardened coconut meat?

At first, the coconut is filled with liquid endosperm. Later when it ripens, the outer layers form brown fibrous covering, and the inner solid layer turns brown and hardens. Within that, a white layer ...
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How do plant cell divide without centrioles?

Most plants do not have centrioles, so what organelle enables them to multiply?
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Why don’t plant cells need centrioles? [duplicate]

I’ve just learned about cell division and I noted that plant cells don’t have centrioles but still undergo cell division. I’ve read a few documents about it and wondered why plant cells don't have ...
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148 views

How many nutrients do trees process daily?

Is this tree fact below that I have found on social media sites true? I don't know the source of the quote. It's pretty amazing. I'll be glad if someone can provide the source too! Natural Wonders ...
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Which are mobile and immobile elements in plants?

I am confused with this element or nutrient classification in the plants, since some authors set elements like $\ce{S}$ and $\ce{Ni}$ as mobile and other as immobile elements (Citation 1, 2, 3, 4, 5). ...
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plant uptake of large molecules

I have read several studies concluding that plants can indeed take up molecules with a molecular weight larger than 390 g/mol. Does this mean plants do also take up large molecules like hormones if ...
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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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1answer
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How can Valonia ventricosa cells get so big?

Valonia ventricosa are single-celled algae that range between one and few centimetres. In rare cases, they can reach sizes exceeding 5cm. They range from grass-green to dark green, and some are even a ...
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Is it normal for corn to have multiple ears in one place?

I have (out of a mistake) one corn plant in my greenhouse and it made 4 cobs in one place. Is that normal?! I never saw something like this before.
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What determines the spiral direction of plants?

Some plants and vines spiral clockwise as they go along (right direction) and some spiral anticlockwise (left direction). What determines which direction they spiral along? At first, I believed it to ...
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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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620 views

Potato Power. Self sustaining medium using a living potato plant possible?

The second picture are potatoes wired in parallel. I understand that the potato is the medium for a chemical reaction between the copper and zinc. That aside, would wire and in soil potato plant ...
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If plants “alternate generations” between sporophytes and gametophytes, why don't we say the same of humans?

I've been reading on Wikipedia about how plants alternate generations between a diploid sporophyte (usually the dominant part) and haploid gametophyte (in flowering plants, the pollen and ovule sacs). ...
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Living potato clock? [duplicate]

Could a potato stay alive and power a clock while growing in the ground? I know how a potato clock works as a electrochemical cell and involves chemistry, but I am only interested in a growing ...
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4k views

Could plants do photosynthesis at moonlight?

Related to this and this but not exactly same; could plants do photosynthesis at moonlight or more dim-intensity light?
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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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Apoplast pathway, down a water potential gradient or not?

So, I was doing a AS level MCQ, the question tells us that water passes across the leaf tissues by different routes as a result of 1) differences in water potential 2) the pull transmitted by ...
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185 views

Liquid that comes out raw mangoes

What is the composition of the liquid that comes out of a raw mango when you break it off from its stem? It oozes out some sort of juicy liquid. Any idea what that is? Also, is it edible?
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Is there a LD50 for CO₂ for plants? [duplicate]

I frequently hear the argument when talking about climate change that high levels of CO₂ in the atmosphere is an advantage, not a problem, because it makes plants thrive. However, can't too much CO₂ ...
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1answer
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What kind of house plant is this?

This is a house plant I have that I love but I don’t know what it’s called. I’d love to research it and even buy more but it’s name is a mystery. Picture taken in Ontario, Canada.
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Pits, symplastic or apoplastic pathway?

After water has moved through the endodermis through the Casparian Strip, water continues to move down the water potential gradient into the xylem vessels through the pits, is movement through the ...
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How do trees manage to grow equally in all directions?

I was walking down a road with these beautifully huge trees when this question occurred to me. Large trees with many thick branches have to grow equally in all directions, or they would tip over. Is ...
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In biological nitrogen fixation, the electrons required to reduce dinitrogen to ammonia are provided by which compound? [closed]

The reaction is as follows: N2 + 16ATP + 8e- + 8H+ → 2NH3 + H2 + 16ADP + 16Pi From where are the 8 electrons coming from? We know that in photosynthesis, the electrons are supplied by the oxidation ...
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Why do animals use glycogen for their polysaccharide storage whereas plants use starch?

The polysaccharide storage form of glucose in animals is glycogen, whereas in plants it is starch. Both of these are polymers of α-glucose with α-l,4 glycosidic linkages and α-l,6 glycosidic branch ...
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What happens with the prothallus after fertilization?

The prothallus is the small gamethophyte stage in pteridophytes. What happens with it after the fertilization and growth of the sporophyte? It stay attached to the sporophyte? It degenerates?