关键词：农作物;生理学;二氧化碳;营养;光周期;光合作用;植物生长;辐射;呼吸;幼苗;种子;土壤;物种多样性;柳枝稷;蒸腾;水使用
摘 要：In this chapter, we review the physiology of switchgrass from seed dormancy till the effects of water and nutrie nts stress on grown plants. These characteristics are presented and discussed mainly at the canopy and whole-plan! level with emphasis on the agro-physiology of the speci es in view of the possible contribution of crop physiology to agricultural de velopment . Swilchgrass is noted for the variable degrees of seed donnancy regulated by endogenous and exogenous factors that determine the successful seedli ng estab lishment. Plant growth rates are determined by temperature while the reproductive phase is controlled mainly by pbotoperiod. There is also evidence that some physiological attlibutes, such as photosynlhesis, transpi ration, and waler use efficiency differ between letraploid, hexaploid, and octoploid ecotypes. But despite these ditTerences, in general switchgrass combines important attributes of efficient use of nu trients and water with high yields thanks to its ability to acqu ire resources from extended soil volumes, especially at deep layers. Moreover al canopy level , resou rcescapture and conservation are determined by morpho-physiological characteristics (C4 photosynthetic pathway, stomatal control of tran 'piration, high leaf area index, low light extinction coefficient) that enhance radiation use efficiency and reduce carbon losses. However, specific information on switchgrass physiology is still missing, in particular deeper understanding of physiological principles controlling the water and nutrients acquisition mechanisms and allocation under suboptimal growing conditions. The physiology of tillering and root respiration are also factors that need further investigation.