4.2: Acquisition of resources in plants (2023)

Cation exchange

Many of the nutrients who need soil plantsCations.}} \).The soil particles often have a negative load, so that these compounds are responsible due to the attraction between opposite loads in the floor particles.In this way, they can first absorb the roots of the plants, they must first be separated from the floor particles.(Illustration \ (\ Pageindex {1} \)).In the exchange of cations, the concentration of the protons (\ (\ ce {h^{+}} \)) in the soil increases in two ways.{H^ {+} \) ions directly on the ground.Second, breathing in root cells \ (\ ce {CO2} \) on the floor, which reacts with floor water to form carbon dioxide and free protons ioniza:

\ [\ S {Bad + your right <=> haka <=> e^ +} + haas^ {-} \]

The ions \ (\ ce {h^{+}} \) adhere more to the floor particles negatively loaded as mineral cations such as \ (\ ce {mg^{2+} \) and \ (\ ce (ce). {Ca^{2+} \).As a result, ions \ (\ ce {h^{+}} \) take the place of mineral cations in floor particles and let these connections on the floor are easy, where they can be absorbed by plant roots.

Root mutualism

To increase the amount of nutrients obtained from the soil, plants have developed several courage with other soil organisms.MutualismIt is a type of interaction of the species in which both types benefit from interaction.In this section we will discuss two root mutualism: mycorrizen and root nodes.

Mycorrhiza relationships are formed between the roots of many plant species and a variety of floor fungi.They pierced the root.The root of the plant and fungal hyphae can replace nutrients.Fungi are heterotrophic, so that the fungus is obtained from the plant by glucose.Since glucose.Many hyphae are microscopic and have a very high proportion of areas at volume, they can be much faster than the roots of macroscopic plants, they access soil nutrients.After the plant, the plant benefits by significantly increasing its ability to absorb nutrients of all kinds in all types of earth, wherever the body of the fungus exists.

Mycorrhiza relationships are found in two categories wide: ectomicorrizen and endomicorrich.In wooden plants, including frequent trees.Endomicorrin fungi penetrate the cell walls of the roots and grow between cell walls and cell membranes of root cells, which sometimes form tree tree structures called Arbusken (Fig. 4.2.2).In each part of the soil profile, the plant can also access access to nutrients, which contain the extensive fungal hyiphenous networks, which increases significantly due to the amount of nutrients available for the plant.While most are generalists and all imprinted soil nutrients that the plant needs in exchange for glucose from photosynthesis.

Root nodes are a different form of root symbiosis.The root nodes are only formed among legumes (family members of Fabaceae plants, including peas and beans) and a group of floor bacteria called floor bacteriaRhizobia.This relationship is mutually, but also more specialized than the exchange of mycorrhizae.In this case, the heterotrophic rizobia also receives glucose from the plant, and the plant receives nitrogen from the bacteria (illustration \ (\ pageindex {3} \)).Nitrogen is an important plant resource and is incredibly difficult for plants.The greatest amount of nitrogen on Earth is n in the form of N₂Gas in the atmosphere that plants cannot use due to the strong triple union between the two nitrogen atoms.₂In biologically useful forms (such as ammonium, NH^{4+ +}), A process that is known as nitrogen fixation.In contrast to the mycorrizen, the root nodes are macroscopically and can be easily seen with the naked eye.At work 2 will examine an example of root nodes: scientific acquisition in eukaryotic organisms.

photosynthesis

In the simplest case, photosynthesis is the process, through the Lichtengie and \ (\ {CO2} \) plants of the atmosphere to build glucose molecules (sugar).If the stored energy is released, which means that it is available for the system to use growth, reproduction, etc.

The visible light contains wavelengths of 300-750 nanometers (NM) and plant leaves contain photosynthetic pigments that absorb parts of the visible spectrum.And vegetables, so most plants seem greenish.

Remember that photosynthesis consists of two stages: the reactions in which the energy of the light is absorbed by the pigments and is maintained in short -term energy molecules, such as the adenosyntrifosphate (ATP) and NADPH;and the reactions used by these energy molecules to \ (\ ce {CO2} \) to record, and their conversion into glucose (illustration \ (\ pageindex {5} \)).-The dependent reactions or simply light reactions, refer us to the second sentence of reactions such as glucose generating reactions, although sometimes they are also called independent reactions of light or the Calvin cycle (-benson).Generating reactions "as more precise and more precise and more precise and more precise descriptive. For example, the generation of glucose reactions is not really independent of the Licht, because they depend on the energy that is stored in the form of ATP and NADPH for the reactions for the reactionsof resin finished.

There are three different "types" of photosynthesis that are known as routes.The most common photosynthesis route isC3 road(Illustration \ (\ Pageindex {6} \)), called because the product of the first reaction is a 3 -carbon molecule.Developing approximately 2.5 billion years ago.On route C3 all Mesophyl cells in the photo sheet.The surface of the leaf).

Route C3 has two main costs.The first costs are the loss of water: to obtain \ (\ ce {co2} \) from the atmosphere to the leaf, where the mesophilic cells can absorb it for photosynthesis, the sheet must open its sheetStomas(Pores in the epidermis).Process calledPhotorerspirationcalled because it consumes or₂and generates \ (\ ce {co2} \) (as breathing) and contains the photosynthetic proteinRubisco.The molecule that \ (\ ce {co2} \) absorbs from the air called Rubisco can also join O2.There is a lot of photographic piracy in a cell.(\ Ce {co2} \) are high.

The plants that carry out C4 photosynthesis have developed a mechanism to avoid these disadvantages of photosynthesis C3C4 -Way(Illustration \ (\ Pageindex {7} \)) is appointed according to the fact that the product of the first reaction is a 4 -carbon molecule.Carbon fixation and Calvin cycle in the same place and time.Rubisco obtains a \ (\ ce {co2} \) molecule of the air dream of the leaf and starts immediately with the Calvin cycle.For carbon fixation, which then moves for the package to the package, so Rubisco is completed the Calvin cycle.In this way, the C4 plants avoid photorerspiration by \ (\ {CO2} \) in the cells in which Rubisco works, and by using PEP -C (which cannot be bound to oxygen) used for the first CO2 record of CO2.Concentration \ (\ ce {CO2} \) In the cell rifle cells allow C4 plants to close their stomata if the environmental conditions are warm are dry so that it can save water and, at the same time, maintain its high photosynthetic activity.However, moving from \ (\ ce {co2} \) to the pod cells of the beam works against the degree of concentration and, therefore, requires energy.Plant, 2 plus ATP -Negimeolules than under photosynthesis C3.The C4 -WEG is, therefore, more advantageous in environments with higher temperatures and drier conditions (if not extremely dry) than those preferred by C3 plants.The concentration of \ (\ ce {co2} \) in the pod cells of the package also means that the plants C4 under the low concentrations \ ({CO2} \) are cut better than the plants C3.

The third path of photosynthesis is called CAM, an abbreviation for Krassulacean's metabolism -cebe -ceure, since this path was first discovered in the family of Crassulaceae plants.These processes in the period (Fig. 4.2.8).Overnight., lift plants use PEP-C to repair carbon, which then converts to wheel acid and is stored in the cell vacuola during the night.retired from the vacuum and becomes again \ (\ ce {co2} \), with Rubisco completing the Calvin cycle.Due to C4 photosynthesis, however, the conversion of \ (\ {CO2} \) in and of wheel acid and its storage in vacuum chamber plants costs two additional ATP energy molecules (in V.totosynthesis) for each glucose molecule created.-The plants C4.

Restrict nutrients and growth commitments

The plants are exposed to particularly complex commitments in growth, since investments have been made from investment in soil growth (leaves, stems, etc.) reduced access to underground resources and vice versa and underground (water, other nutrients), Plant resource patterns are influenced by growth.An important consideration of these commitments is which nutrients is restricted for the growth of plants in a certain environment.The nineteenth century developed an analogy to describe how different nutrient mirrors influence plant growth.Plant's resources compared to a barrel made of wooden slats (Fig. 4.2.9).Availability of this nutrient in the ecosystem, Verglichen with the need for the plant (that is, even if a nutrient in the ecosystem is rare, its coffee with milk can be high, if a plant needs very little of this nutrient).Ecosystem.The amount of water that the race can contain is notDriven by the height of the highest Lattens or even the average height of the slats;It is completely controlled by the height of the shortest milk with milk.Similarly, plant growth is not determined by the general availability of resources, but by the availability of limited resources.Resource is the resource, which has the least availability compared to the way in which the large part of this resource needs the system (that is, the shortest Latte).The growth of the plant determined in the ecosystem.

Illustration \ (\ Pageindex {9} \): Diagram of the law of the analogía of the minimum of execution.AU wikimediaum modified².

The slats in Fig. 4.2.9 contain resources on the soil and underground.Changes in the availability of resources on or below the land will influence investment investments in these areas.Root relationship to shots, abbreviated roots: shoot.In this case, "shoot" includes all growth growth, including stems, leaves and reproductive structures such as flowers or taps.An increase in the availability of underground resources means that the system invests more in the fabric on the ground, which leads to a reduction in the root driving ratio.This can initially.v sound;However, if underground resources become richer, they are relatively less restrictive than land resources. Therefore, the system benefits by increasing its investments in generally changed resources by increasing their investments in the growth of the shooting,It is reduced, which is reduced, what is reduced: the root ratio: plant shooting also applies otherwise if supernated resources increase availability.

photographic credits

1. https://commons.wikimedia.org/wiki/File:Figura_08_02_05abcd.jpg
2. https://commons.wikimedia.org/wiki/File:Minimum-Tonne.svg