Different Kinds Of Rape Seedling Root Response On Attack Stress

This study used indoor hydroponics, choosed Brassica napus cv “shanyou 16” and cabbage rapeseed cv “baizayihao” as research materials, treated with different concentrations of Attack(0.001mg/mL, 0.017mg/mL, 0.033mg/mL, 0.056mg/m), test the rape sedling root on morphological structure and physiological metabolism response on Attack stress. The main results were as follows:(1)The two kinds of rape bud seedling root had similarly response on Attack stress under all test concentrations. Tap root, lateral root and root hair length were shortened. Root biomass of amount accumulation were inhibited. So in order to avoid injury, user should be strictly in accordance with the use of herbicides in production.(2)The two tested rape bud seedling root also had different response on Attack stress. Results showed that “Baizayihao”held stronger tolerance to Attack stress than “Shanyou 16”. The performance is that the root length, root dry weight, shoot dry weight and root shoot ratio of bud seedling are felled more than “baizayihao”. Root hair and lateral root were inhibited higher than “Baizayihao”. On the formation of root system, “Baizayihao” held higer tolerance than “Shanyou 16”.(3) Physiological indices indicated that, under Attack stress, the accumulation of chlorophyll in rape cotyledons were inhibited. Soluble protein and soluble sugar content were increased. At the concentration treatment of 0.001-0.033mg/mL, in the antioxidant oxidase(SOD, POD, CAT & APX) activity were increased, under the highest stress concentration 0.056mg/mL, the activity of SOD and ATP were decreased. The physiological and metabolic changes of the rape bud seedling are the physiological mechanism of the resistance to Attack stress. Compared to the two kinds of rape, the antioxidant enzymes(SOD POD, CAT & APX) activity in the root of “Baizayihao” were higer than “Shanyou 16”, root membrane system serious damaged than “Shanyou 16”. This is the physiological reasons that the root of “Shanyou 16” was inhibited more than “Baizayihao”.(4)At morphological anatomy structure of rape root bud seedling root had response on Attack stress. The main performance that the root tip of rape was expanded, root cap, quiescent center and meristematic cells of the boundary were blurred, cells arranged chaotically, cell gap were increased. Epidermal cells had irregular morphology in the root hair zone. And partial were falled off, Unable to produced hair. Pericycle cells became small, arranged chaotically, cell between each other very closely. Thus,the differentiation and development of Pericycle cells were blocked. Ultimately, the formation of lateral root were affected. This is the cytological mechanism of the resistance of the rape root tip, by inhibiting the growth of lateral roots and root hairs to reduce the absorption of herbicides. Under Attack stress, the diamete of vascular cylinder and vessel were decreased, and with the increase of the concentration of stress, the stronger the effect was. In order to impede herbicide conduction, to protect the ground part against stress damage. And “Baizayihao” showed better drug resistance under Attack stress.