Hot answers tagged plant-physiology
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The short answer is that as long as the vegetable/fruit is fresh looking - i.e. the cells have not disintegrated - they will be respiring, many cells will be functioning quite normally, and the plant is still technically alive. In cases where the part of the plant we treat as a vegetable is a part intended for reproduction (e.g. a seed, or a tuber like a ...
15
Cellular respiration in plants is slightly different than in other eukaryotes because the electron transport chain contains an additional enzyme called Alternative Oxidase (AOX). AOX takes some electrons out of the pathway prematurely - basically the energy is used to generate heat instead of ATP.
The exact purpose of AOX in plants is still unclear. Plants ...
13
There are several key ways in which rising atmospheric CO2 concentrations will affect photosynthesis, and these are related to the different types of photosynthesis. In order to properly answer your question, I'll provide some background about photosynthesis itself.
Photosynthesis evolved in a high-CO2 atmosphere, before the oxygen-enrichment of the ...
12
There are quite a few questions and thoughts in there, I'll try to cover them all:
First, to correct your initial word equation: During photosynthesis, a plant translates CO2 and water into O2 and carbon compounds using energy from light (photons).
You are correct to assume the C is further used for the growing process; it is used to make sugars which ...
11
It looks to me (although I'd want to use a microscope to check) like the black dots are xylem. When you cut the fruit, you've severed the xylem and also exposed the flat surface. Three main things have then happened:
The increased surface area has led to the 'fleshy' part of the fruit contracting as the cells dehydrate.
The stiffer, lignified xylem tubes ...
10
I wanted to add a little more to the excellent answer above, especially since the OP asks about research into this question in a "real-world context".
There is a substantial body of evidence on exactly this question that comes from experiments at "Free Air CO2 Enrichment" (FACE) sites. FACE is an experimental method/technology in which standing ecosystems ...
10
There are some other good answers which provide part of the picture, but I think there is a fundamental organising principle which has been missed. Konrad has touched on it in his answer.
The reason trees, and most plants, tend to grow equally in all directions is that they have iteratively generated branching and radial symmetry which is controlled in a ...
9
Plants will be respiring continuously, which is an exothermic process. Therefore the plants will be producing a small amount of heat. The protection from frost may be more a result of the vastly smaller convection current of the coat compared to the atmosphere rather than by reducing any conduction away of heat produced by the plant, however.
Keeping the ...
9
There are 5 answers, all "yes".
First: there exists at least one animal which can produce its own chlorophyll:
A green sea slug appears to be part animal, part plant. It's the first critter discovered to produce the plant pigment chlorophyll.
The sea slugs live in salt marshes in New England and Canada. In addition to burglarizing the genes needed ...
8
Most water moves up through the xylem by capillary action. Imagine dipping a pipette into a small pool of water; the water would rush up into the pipette. Or, imagine dipping the edge of a paper towel in water. The water "runs" up the paper towel. This is capillary action.
As water evaporates out of the leaves and such in higher regions of the plant, a ...
7
This is a question for which, I think at the moment, we don't have a clear answer.
It is important to bear in mind that the leaf plays a number of important roles in the plant (photosynthesis, thermoregulation etc.) so leaf shapes probably evolved through a process of successive trade-offs. This may make it difficult to identify the exact selection ...
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They don't always. For example, this apple tree grows just outside my window:
So far, it hasn't fallen over yet. The reason it grows that way is because all the light is coming from the right side of the picture: the tree leans roughly to southeast, while the building is to southwest of it and casts a shadow on the center of the yard for much of the ...
7
Animals and plants are both classified as Eukaryotes, and as such can form large, complex, multi-cellular organisms. There are several major differences at the cellular level that distinguish the 2 Kingdoms (Animalia and Plantae). Without getting technical, the most crucial difference in relation to your question is that plants contain chlorophyll, and as ...
7
If you mean the efficiency at which plants convert light energy to chemical energy (in sugar or other reduced C compounds) then there is definitely variability between plants, both at the species and individual level. The photosynthetic efficiency WP page gives ranges of between 0.1 and 8% of total solar radiation converted to "biomass", but these values are ...
6
Firstly, different genera of trees can occasionally be successfully grafted. For example, quince, genus Cydonia, may be used as a dwarfing rootstock for pear, genus Pyrus.
However, it is true to say that this is the exception rather than the rule.
In the case of plants in the family Cactaceae, I would suggest that grafting is usually successful for two ...
6
Pumpkins, squashes in general, grow on vines, while apples grow on trees. Vines are fast growing and trees are not. Zucchini can be quite large; cucumbers, too. Pears, plums, peaches and other tree fruits do have a reduced variation in fruit size. While I do not know the answer to your question, my background in plant biology tells me that this is an ...
6
First let me say this: I am no gardener. Every plant that enters my home or yard dies a slow death of neglect. I do have some experience trying to remove weeds from other non-weeds, and there is a practical aspect of "uproot every GMO plant" that I think may be impossible, but this is speculation. Let's get into a literature review.
A frequently cited paper ...
6
Yes, plants of all sizes can have cancerous growths.
Agrobacterium tumifaciens, the causative agent of crown gall disease, produces what is called a tumor. See this link for detailed information on these growths. Alternatively, use a plant physiology textbook to look up the above terms. (Here, is where a textbook is better than a single abstract in PubMed.)
...
5
Actually, the units are °C days or °F days. The units are mostly given in the typical name, Growing Degree Days where which temperature unit is meant is understood from the context. Much more important is knowing the base temperature ("T_base") since this value can be different in different usages, even for the same type of organism.
5
The pith (medulla) forms part of the ground tissue system of a plant, and specifically it is the ground tissue which lies interior to a plants vascular tissues (xylem, phloem etc.)
The ground tissue system is responsible for much of a plants metabolic functioning, and contains various specialized cell types which aid in photosynthesis and storage of ...
5
The green pigment is indeed chlorophyll, and the fruits do perform photosynthesis. It's not just "fruiting" plants that do this either. Some shading experiments i saw estimated that up to 30% of the sugars assimilated into the barley ears (basically the grain) can come from photosynthesis occurring in that organs.
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In general, plant cells only undergo differentiation at special regions in the plant known as meristems. Two of the primary types of meristem are the root apical meristem (at the tips of roots) and the shoot apical meristem (at shoot tips)^. Within the shoot apical meristem the plant cells divide and begin to differentiate into different cell types (such as ...
5
During the daylight, the plant is photosynthesising faster than it is respiring so there is no net uptake of oxygen (the oxygen of course being produced in the as part of the photosynthesis).
Of course, this only applies for tissues where photosynthesis is occurring. In the roots of the plant, oxygen must always be present in the surrounding soil/growth ...
5
Growth in plants is tightly controlled by auxins – plant hormones. Auxin itself usually has an inhibitory effect on growth. As far as I know there is no active control to restore plant symmetry once it has gone awry (but I could be wrong!) but the inhibitory effect of auxin synthesised at the meristem and diffusing in all directions causes a symmetrical ...
5
As hinted in other answers, the key problem with a pure oxygen environment would be the inability to photosynthesise caused by the absence of carbon dioxide.
The overall equation for photosynthesis (the process in which energy from the sun is harnessed to fix inorganic carbon dioxide into organic molecules that are of use to the plant) is:
6CO2 + 6H2O ...
5
In high school, we did an experiment that showed this.
Basically, if you take a glass of water, and let it sit out, perhaps in front of an open window, it will eventually lose water due to evaporation. It may take a few days/weeks to really see a large difference, but the level will go down. But, if you take a few flexible straws, put them in so the bendy ...
5
Shigeta submitted his answer as I was writing this!
Sanseveria is one of a wide group of plants (mainly succulents) that adopt a photosynthetic strategy referred to as crassulacean acid metabolism (CAM).
Recall the basics of photosynthesis. The light-dependent reactions use energy from captured photons to generate ATP and NADPH, with the generation of O2. ...
4
I'm no expert, but I liked this question and did a quick literature search:
Xylem cells are certainly dead at maturity, and it is these cells that make up the majority of what we call wood. However, wood also contains other tissue types, some of which have live cells at maturity. From what I can glean here and here, it is ray parenchyma tissue that is ...
4
There have been several experiments in growing plants in microgravity (strictly speaking, we do not achieve "zero-g" since astronauts remain in orbit about the Earth).
Changes in plant growth due to the influence of a gravity field is sometimes called gravimorphogenesis. More specifically, gravitropism is a differential growth response of plant organs to ...
4
This is basically the same that happens after pruning and involves a basic hormonal regulation mechanism in the plants.
What happens is that the cut piece of the wood forms a new meristem which allows the growth of new organs. What’s important is that there is no other growth happening nearby, since that would hormonally inhibit any further growth. This is ...
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