The plant as a whole organism, and ecological factors

The part of the environment that affects plant life is an ecological factor. Abiotic factors are non-living nature: soil, temperature, water, light, air. Soil gives water and minerals; light and temperature control photosynthesis, respiration, growth, germination and fruit ripening; water makes up a large part of a plant’s weight (roughly 60–90%); CO₂ in the air is needed for photosynthesis and oxygen for respiration, while wind affects transpiration, pollination and dispersal. By their relation to light plants are light-loving or shade-loving. Biotic factors are living nature: bacteria, fungi, animals and other plants. Nodule bacteria on legume roots take nitrogen from the air and feed the plant; soil microorganisms decompose organic matter; birds and animals disperse seeds. Plants also affect one another: parasitic plants such as dodder (zarpechak) and broomrape (shumg‘iya) live at the expense of another plant and harm it; juniper, pine and poplar release phytoncides that kill microbes. The human factor can be positive (growing crops, restoring forests, greening settlements) or negative (felling forests, over-collecting and overgrazing, pollution). The fall in the level of the Aral Sea spread toxic dust and salt over soils, and tugay forests along rivers began to die.