干旱区生态环境知识资源中心

We aimed to determine the ecological role of three seed morphs observed for the first time in a desert population of Lotononis platycarpa (Fabaceae), with respect to their germination requirements. Seeds sorted by seed coat colour (olive green, orange and brown) were germinated under laboratory conditions under two photoperiods (12/12-h light and continuous dark) and three alternating temperature regimes (15/25, 20/30, 25/35 degrees C). We found that the three distinct seed types differ in their seed mass, germination percentage and speed of germination. Overall, the light-incubated seeds germinated with higher percentages than seeds in the total darkness. Furthermore, seeds with orange coat germinated with higher percentages at 15/25 and 25/35 degrees C (up to 60%, for both) and significantly faster than the other two colour morphs. Our results suggest an adaptive significance of seed colour heterogeneity in the harsh desert habitat inhabited by the study species.