薏苡属种质资源的生态适应性比较

Comparison on Ecological Adaptability of Germplasm Resources of Coix

为探索薏苡属植物适应环境的形态生理特性,以我国4个不同纬度地区的薏苡属野生种质资源为实验材料,研究其物候期及主要农艺性状,并采用Li-6400便携式光合仪测定其不同月份的气体交换特性.结果表明,薏苡同一朵花中雌雄蕊绽放的时间相差3~4 d,由此导致了异花传粉的特性;薏苡属植物形态多样,生长发育时间有很大差异,纬度越高生长越快,生命周期越短,高纬度的窄果薏苡(CS)生育期比低纬度的水生薏苡(CA)少了82 d;纬度越高植株越矮,CS的株高仅67.9 cm,但分蘖数最多;果实色泽、大小多样,没有明显的地域特性;薏苡在营养生长旺盛的时期净光合速率最高,CS的净光合速率在6月份可达31.1μmol·m^-2·s^-1,蒸腾速率却很低,由此提高了水分利用率以适应水分缺乏的原生地气候;CA的净光合速率在整个生育期变化不大,蒸腾速率在8月份最高,以减少高温对植株的伤害.薏苡的形态生理特点体现了对原生地域温度及水分的适应性.

In order to explore the morphological and physiological adaptation mechanism of Coix.The four wild germplasm resources of Coix at different latitudes regions in China were collected.Their phenological period and main agronomic traits were compared.The gas exchange characteristics of Coix in different months were measured by Li-6400 portable photosynthetic apparatus.The results showed that the time between the male and female stamens in the same flower differed by 3-4 d led to the characteristics of cross-pollination.The growth and development time of Coix varied greatly.The higher the latitude,the faster the growth and the shorter the life cycle was.The Coix lacryma-jobi var.Stenocarpa(CS)which at high latitudes was 82 days less than the Coix aquatica(CA)at low latitudes.The higher the latitude,the shorter the plant was.The height of the CS was only 67.9 cm,but the number of branches was the most.Fruit color and size were varied,but had no obvious geographical characteristics.The net photosynthetic rate of Coix was the highest during the period of strong nutrient growth.The net photosynthetic rate of CS reached 31.1μmol·m^-2·s^-1 in June,but the transpiration rate was very low,which increased the water use efficiency to adapt to the water-deficient native climate.The net photosynthetic rate of CA did not change much during the whole growth period,and the transpiration rate was the highest in August to reduce the damage of high temperature to plants.The morphological and physiological characteristics of Coix reflects its adaptability to temperature and moisture of their native region.