Questions tagged [plant-physiology]

Study of the normal functioning of plants and plant cells

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8 views

Protein content in chemical composition of different phyla?

The protein content in the human body is roughly 15%, what are the percentages for other organisms? Bacteria, plants, fungi, protozoa, etc.
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How can I make legal mature female Cannabis plants to Flower in home during March (springtime)? [closed]

In December 2019 I purchased 4 Cannabis seeds Legally in Canada.Two of my plants are now about 100 cm tall. I am using wide-spectrum LED grow lights and have fertilized them both. I started with 16 ...
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If plants benefit from carbon dioxide, why is car traffic something bad?

This is going to sound really stupid or as a joke, but... Ever since I was a little kid, I have been confused about the following: Humans need air/oxygen to breathe in order to live. Plants/trees/...
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Does photosynthesis begin instantly when a plant is exposed to light?

I'm curious to know if the process of photosynthesis has a "ramp-up" time to become useful to a plant, or if it begins instantaneously when the plant is exposed to light after a period of darkness. ...
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Why do guard cells open stomata when they are swelling?

As the concentration of potassium inside guard cells increases, water enters the cell by osmosis. But why does the swollen causes the stoma to open? Does it relate to the thickness of the cell wall? ...
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22 views

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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18 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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2answers
53 views

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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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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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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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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126 views

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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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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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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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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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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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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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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214 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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192 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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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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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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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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32 views

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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27 views

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?
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Reasoning for Stomatal Distribution Between Monocot and Dicot

When you compare the stomatal arrangement of bean and corn plants under a microscope, you notice that the corn's stomata arrangement is much more organized and linear then the beans. I am wondering ...
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How long can cytoplasmic streaming be in an isolated leaf?

Here is an interesting video demonstrating the effect of cytoplasmic streaming: cytoplasmic_streaming of a leaf We see the leaf has been isolated from its original body. I wonder how long can this ...
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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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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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141 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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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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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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75 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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404 views

Why does the seed of the coconut tree have a liquid in it?

What is the purpose of water in the coconut seed? The reason I ask this is that I was reading about coconut water and all the benefits it has for us Humans. But why does the tree put a liquid in the ...
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27 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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1answer
742 views

Difference between vacuolar and symplast pathway [closed]

what is the difference between Vacuolar Pathway and Symplast Pathway ? Is the symplast pathway does not take into account the vacuole to vacuole movement?
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1answer
62 views

Why was cotton chosen to grow on the moon?

The choice of plants for the first lunar ecosystem is a bit unusual. They are growing cotton, rapeseed and potatoes. Why did the Chinese scientists choose them? Is it because of their ability to ...
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1answer
25 views

Why are Arabidopsis plant seeds being sent to the moon and not other seeds?

The latest Chang'e-4 rover brings an entire ecosystem with it, including Arabidopsis plant seeds and silkworms. My question is: why Arabidopsis? Is this question conclusive without having to ask ...
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237 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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1answer
25 views

Do unique communities of bacteria form inside water storage in plants?

I assume that plants, like animals, have an ability to fight off bacteria that invade their cells (support: here and here. However, water often harbors quite a bit of bacteria in even unsuspecting ...
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1answer
139 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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1answer
469 views

Why aren't leaves black?

I s'pose this is a variant of the age-old question, "Why are leaves green?" It's fairly easy to ask teh internets and find plenty of answers for that one. I have a different but related question: ...
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194 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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841 views

What does the acronym ‘PIN’ stand for referring to PIN proteins in plants?

There are so called PIN proteins, or PIN-formed proteins, in plants. What does this acronym mean? Wikipedia briefly explains the function of the protein but not the origin of the name. It's not ...
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525 views

Why does photosynthesis occur even in blue light when the photocentres are activated in red light

From Engelmann's experiment Engelmann used this device to illuminate a strand of Cladophora (not Spirogyra) with light from the visible spectrum, exposing different sections to different ...
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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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