|
Purple pearl millet (Pennisetum glaucum'Purple Majesty ') is the world breeding industry \and ornamental value. In recent years, Royal Purple Valley, with its excellent ornamental characteristics, are being promotion in urban gardens around the building, is likely to develop into an important city in green plants. The experimental simulation of high and low two kinds of stress conditions, Royal Purple Valley studied under two conditions in this physiological and biochemical response of, and also studied the salicylic acid (Salicylic acid, SA) alleviate the harm suffered mechanisms to Royal Purple Valley clarify under temperature stress response mechanism for the purple pearl millet seedlings planted in Chongqing reference. The results are as follows: 1. High and low temperature stress, the root activity decreased rapidly, root length, root surface area and root volume while lower than normal controls. SA significantly improves the plant's root surface heat stress and cold stress plants root activity. (2) under high temperature stress, Chla and Chlb content first and then decreased and eventually lower than the control; Car content is also slightly lower than controls, Pn and Cond significantly decreased, Trmmol gradually increased, but its greatest strength is significantly lower in the control, indicating that high temperature stress destroys the structure of chloroplasts, purple pearl millet leaf photosynthesis under heat stress impeded; cold stress, Chla and Chlb content first and then decreased and eventually lower than the control, Car significantly reduced, Pn and Cond basically at the lowest level, Ci increased significantly, Trmmol up briefly in the early, after they have been maintained at a low level, thereby illustrate Imperial Valley under low temperature stress purple photosynthetic system has been severely damaged, photosynthesis almost at a standstill. SA significantly improved high temperature and low stress levels Chla and Chlb outside, SA treatment, the seedlings under high temperature stress Pn, Cond, Gs and Trmmol have risen, while Pn seedlings under low temperature stress has increased, Ci has gradually decreased while Cond and Trmmol no significant change. 3 Royal Purple Valley under high temperature stress suffer more serious injuries, the relative conductivity and MDA content increased significantly, the soluble protein content in heat stress significantly decreased at day 7, proline content increased in the early stages of heat stress obvious; under low temperature stress, MDA content increased significantly, soluble sugar and proline content is much greater than the control level, indicating purple pearl millet are more sensitive to low temperature stress. SA treatment reduced the Royal Purple Valley under high temperature stress relative conductivity and MDA content increased soluble protein and soluble sugar content; while under low temperature stress treatment not only improves SA Royal Purple Valley soluble sugar content and reduced free proline acid levels, indicating that SA also increased to some extent, purple pearl millet cold tolerance. 4 under high temperature stress, POD activity was significantly lower than the control, SOD and APX activity will remain at the level of control; cold stress, SOD and APX activity increased rapidly, and the rate of increase greater than the high temperature stress, POD activity remains lower than the control level, GR activity although higher than the control, but when compared to high temperature stress has decreased significantly. This can be inferred, under low temperature stress of intracellular reactive oxygen species generation than heat stress, cold stress on Royal Purple Valley injury is more serious. Heat stress, after SA treatment, SOD activity increased, POD activity weakened further, while the activity of GR and APX is basically unchanged. The SA under low temperature stress reduces the maximum activity of SOD and SOD activity reaches the maximum delay time, while the activity of GR and APX also appeared weakened condition.
|