A common shoot developmental framework for perennial legume species with contrasting morphogenesis

摘要

Little is known about the elementary traits which make temperate forage legumes differ so substantially in their growth habit and morphologies. In the present study, we compared the patterns of shoot organogenesis and of organ growth of six contrasting forage species (namely alfalfa, birdsfoot trefoil, sainfoin, Kura clover, red clover and white clover) during their vegetative phase. An experiment was carried out over two years in a greenhouse under non-limiting water and soil nutrients. Phytomer initiation appeared driven by temperature and highly deterministic in all the species in the absence of competition for light. The temporal sequence of organ growth differed between species. However, organ growth was highly coordinated within a phytomer inall the species, and was independent of the position and axis order when expressed in phyllochronic time. By contrast, organ dimensions at maturity were dependent on phytomer position, and followed a regular function of the rank for all the organs. Overall, a very similar developmental pattern was followed by all the species, but they differed greatly in the absolute values taken by their developmental traits.