亚热带草原的根与芽的比率和植物有机碳的估计:为什么全球平均值不足

Vascular plants, which account for over 90% of the Earth’s vegetation, all undergo primary growth—which lengthens roots and shoots. Many land plants, notably woody plants, also undergo secondary growth—which thickens roots and shoots.

Plant tissue culture is widely used in both primary and applied science. Applications range from plant development studies to functional gene studies, crop improvement, commercial micropropagation, virus elimination, and conservation of rare species.

Plant hormones—or phytohormones—are chemical molecules that modulate one or more physiological processes of a plant. In animals, hormones are often produced in specific glands and circulated via the circulatory system. However, plants lack hormone-producing glands.

Carbon is the basis of all organic matter on Earth, and is recycled through the ecosystem in two primary processes: one in which carbon is exchanged among living organisms, and one in which carbon is cycled over long periods of time through fossilized organic remains, weathering of rocks, and volcanic activity. Human activities, including increased agricultural practices and the burning of fossil fuels, has greatly affected the balance of the natural carbon cycle.

Plants grow throughout their lives; this is called indeterminate growth, and it distinguishes plants from most animals. Although certain parts of plants stop growing (e.g., leaves and flowers), others grow continuously—like roots and stems.

Light plays a significant role in regulating the growth and development of plants. In addition to providing energy for photosynthesis, light provides other important cues to regulate a range of developmental and physiological responses in plants.