光合调控 z-bo 2020-11-02 361

　　The light intensity in the natural environment usually fluctuates frequently and sharply in a short period of time, which is called fluctuating light intensity. When the light intensity increases suddenly, the excess light energy absorbed by the plant leaves is more likely to cause damage to the activity of the photosystem I and affect plant growth. Therefore, fluctuating light intensity is one of the natural light stresses suffered by plants. Revealing the photosynthetic regulation strategy of plant leaves under fluctuating light intensity is of great significance for understanding the adaptation of plants to natural light, and it also has potential for increasing crop yields.

　　Traditional theories believe that ring electron transport, an alternative electron transport pathway, is the main regulatory mechanism for angiosperms to protect the activity of photosystem I under fluctuating light intensity. According to the photosynthetic electron transfer model, the up-regulation of the water-water cycle and the down-regulation of the photosystem II activity can reduce the electron transfer from photosystem II to photosystem I, and prevent photosystem I activity from being damaged by fluctuating light intensity. However, the role of these two regulation strategies in the adaptation of angiosperms to fluctuating light intensity has received little attention.

　　The research team of Zhang Shibao, a researcher of the new species selection and industrialization demonstration team of the Kunming Institute of Botany, Chinese Academy of Sciences, recently conducted research on photosynthetic regulation strategies under fluctuating light intensity and obtained a series of findings: Camellia plants are avoided through the water-water cycle. Photosystem I is damaged under fluctuating light intensity, and the water-water cycle is a more efficient strategy than ring electron transfer; Aesculus uniflora reduces the activity of photosystem II to prevent photosystem I from being damaged under fluctuating light intensity. It is found in wild angiosperms that the down-regulation of photosystem II activity is an important regulation strategy to adapt to fluctuating light intensity; high temperature will aggravate the damage of photosystem I of tobacco immature leaves under fluctuating light intensity, but the photosystem I activity of mature leaves is This is less sensitive; the degree of damage to photosystem I activity under fluctuating light intensity is mainly affected by the weak light background of fluctuating light intensity, and the excitation degree of ring electron transfer under fluctuating light intensity is mainly regulated by the redox state of photosystem I .