Physiological effects of leaf senescence of foxtail millet under different cultivation modes.

To study the physiological effects of leaf senescence and resistant parameters of foxtail millet in different cultivation modes,the experiment investigated the chlorophyll content,photosynthetic rate,SOD and CAT activities,MDA content and soluble protein content in the leaves of foxtail millet among three cultivation modes(flat planting,straw mulching,plastic-film mulching) with 80 kg N/hm2 application and planting density of 120×104～130×104 plants/hm2 on leaf senescence of the foxtail millet cultivar Gufeng 888.The results indicated that leaf senescence and reactive oxygen species metabolism varied with the cultivation modes.Compared with flat farming,straw mulching could increase leaf chlorophyll,slow the speed of leaf aging and the extent of declining metabolism.At the early filling stage,plastic-film mulching could increase leaf chlorophyll,enhance SOD and CAT activities,and lower the malondialdehyde(MDA) content.At the late filling stage,there were a remarkable decline of leaf chlorophyll,a quick leaf senescence and a marked increase of MDA.The SOD and CAT were involved in leaf senescence regulation,synergistically protecting the leaves by reducing the damage from reactive oxygen species,prolonging the functional period of leaves and increasing the yield and quality of foxtail millet.