Succulents refers to plant roots, stems and leaves of three kinds of vegetative organs in at least one is succulent, with a lot of water storage function. And having at least a fleshy tissue, this kind of organization is a kind of living tissue, among other functions, it can be stored in resource utilization in water, deterioration of soil moisture conditions, plant roots can not be absorbed from the soil and provide the necessary water, it can make the plant temporarily from the external water supply and independent living. Sometimes people love to this kind of plant called desert plants or desert plants, this is not accurate. There are many succulent plants growing in desert areas; including cactus, Aizoaceae, Jing Tianke, Apocynaceae, Euphorbiaceae, plant asphodeloideae, Asparagaceae more than 50 families, but not all grow in the desert, the desert is also growing more than many meat plant.
Because of long-term adaptation to arid environment, great changes have taken place in vegetative organs of cacti and succulents, the original leaves in most cactus plants has degenerated into a needle like leaves, in the Euphorbiaceae succulents often only traces or caducous; but still exist in most other families of Succulents in just, has different degree of succulence; stems in cactus not only has instead become the main organ for photosynthesis of the leaves, and because of the change of the thousands of highly ornamental. But many other branch stem succulents does not exist or has only a very short stem. In addition, cacti also have unique organ spines. Therefore, in the description of the morphology, cacti must be listed individually so as to facilitate narration.
With Crassulacean acid metabolism of plants for succulent plants, they are in the night by opening CO then with the combination of absorption, and PEP carboxylase and phosphoenolpyruvate to form oxaloacetic acid, and malate dehydrogenase in the role of reduction of malic acid into the vacuoles and accumulated acid (from pH5 to 3) second days after irradiation; malic acid from the vacuole transported to the cytoplasm and chloroplast in decarboxylation, the release of CO is absorbed by RuBP formation of carbohydrates.
The water storage tissue is mainly in the leaf part. Stems are generally not succulent,
Part of a woody stem. Depending on the degree of drought in the habitat, the degree of leaf differentiation is different. A region of less arid origin; larger leaves and thinner leaves. Such as Aizoaceae flower creeping origin of the Natal province of South Africa, because South Africa is more humid than in other regions, so it has more flowers creeping form thin leaf, plant shape for climbing, not general difference between morphology and flower. With the trend of drought environment, more and more local succulent stems, short leaf more thick; and some species distributed in the Aizoaceae extreme arid area, the whole plant is composed of only one or two pairs of leaves, stems and leaves have all disappeared, is highly succulent.