The concept and basic knowledge of succulent plants
The editor introduces you to the explanation of succulent plants, the concept and basic knowledge of succulent plants, please see the detailed introduction below.
The photosynthesis and respiration of succulent plants
The energy source for all biochemical reactions in plant cells comes from respiration. A large amount of biological energy (adenosine triphosphate, ATP) is produced through the aerobic oxidation or anaerobic fermentation of glucose, providing energy for other biochemical reactions. All cells are constantly undergoing respiration, consuming oxygen and releasing carbon dioxide. Energy metabolism is completed through four steps of cellular respiration: glycolysis, the production of acetyl-CoA, the tricarboxylic acid cycle, and electron transport and oxidative phosphorylation. The site for energy metabolism in cells is the cytoplasm and organelles such as mitochondria.
Photosynthesis and respiration are different but not opposite or contradictory. Because these two processes are completely different biochemical modes: photosynthesis is powered by light and releases oxygen, that is, the process of photolysis of water, producing oxygen and reducing equivalents (nicotinamide adenine dinucleotide phosphate reduced form, NADPH). Reducing equivalents can be considered as a form of biological energy, which is used to fix carbon dioxide to synthesize glucose and other organic compounds. The main site of photosynthesis is the chloroplasts in leaf tissue cells.
The photosynthesis and respiration of plant bodies coexist, each performing their biological functions and missions, and协同. They appear as photosynthesis releasing oxygen and absorbing carbon dioxide; respiration releasing carbon dioxide and absorbing oxygen. The strength of photosynthesis determines the amount of oxygen released by the plant body, but it does not mean that photosynthesis can determine respiration, as there is no absolute dependence between them. The main controlling factor of photosynthesis is light, while the main controlling factor of respiration is temperature. Plant respiration is always present, including during the day and at night; while photosynthesis mainly occurs during the day. This determines that most plants release carbon dioxide and absorb oxygen both during the day and at night; but when there is light, photosynthesis far exceeds respiration, making the carbon dioxide released by respiration almost immediately used by photosynthesis, which manifests as plants releasing oxygen and absorbing carbon dioxide during the day.
For succulent plants, because the cells of this type of plant use the "Crassulacean Acid Metabolism (CAM) pathway." They are different from other C3 and C4 plants. These plants close their stomata and do not or barely exchange gases during the day. At night, it is different, they exchange gases for photosynthesis and respiration, and visually release much more oxygen than carbon dioxide, which is very different from other plants. However, this does not mean that the photosynthesis of succulent plants occurs at night. In fact, these carbon dioxide are stored in organic acids (such as malic acid) in leaf mesophyll cells, and when there is light, these organic acids are decomposed and released in the bundle sheath cells for photosynthesis.
The assertion "Light = Energy" directly illustrates the significance of photosynthesis: converting non-biological energy into biological energy and synthesizing complex organic matter for the organic matter cycle in the biosphere. The organic matter produced can generate more biological energy through respiration, laying the foundation for numerous biochemical reactions. Therefore, it can be said that photosynthesis is the foundation of respiration, existing only in organisms with chloroplasts, while respiration is widespread in the biosphere.
Quantitative analysis of photosynthesis: For C3 pathway plants, converting one molecule of carbon dioxide requires 3 molecules of ATP; synthesizing one molecule of glucose requires 18 molecules of ATP. However, through aerobic oxidation of one molecule of glucose during respiration, 36 or 38 ATP can be generated. It can be seen that photosynthesis is an energy-fixing process, while respiration is actually an energy-generating process. For C4 or CAM plants, 30 molecules of ATP are needed to produce one molecule of glucose, and similarly, the decomposition of one molecule of glucose by respiration still produces 36 or 38 ATP, showing that the metabolic rate of C4 or CAM plants is relatively low, appearing as "slow growth." Although C3 plants consume less ATP than C4 plants, due to the less obvious respiration in C4 or CAM plants, the carbon dioxide generated is immediately used by photosynthesis, so C4 or CAM plants have higher photosynthetic efficiency and stronger ability to store nutrients, appearing as a "succulent and thick" state.
The comparison and analysis of photosynthesis and respiration in C3, C4, and CAM plants discuss the characteristics of the plant kingdom from a physiological and biochemical perspective, analyze the similarities and differences between succulent plants and other plants, and establish the biological status of succulent plants. At the same time, it has laid the theoretical foundation and provided research evidence for the research of succulent plants in horticulture, medicine, genetic breeding, and biotechnology.
More importantly, these basic studies have promoted the development of succulent plants in ecology, classification, cultivation, propagation (especially tissue culture), and genetic breeding.
The above introduction to the concept and basic knowledge of succulent plants is hoped to be helpful to you. Don't forget to come and see more flowering experience and common sense!