Preliminary Research On Effect Of Nap And Phe On Growth Of Matsumae At Vegetative Growth Stage

Organic contaminations come into farmland soil by irrigation of industrial waste water, sedimentation of atmospheric contamination and use of pesticide,hence affect growth and development of crop.The study mainly investigates the effect of naphthalene(Nap) and phenanthrene(Phe) on growth of Matsumae at vegetative growth stage,and clarifies harmful mechanism of paddy ,and at the same time discusses primarily adaptive mechanism of paddy under the stress of two organic contaminations.The study used Matsumae plant as experimental materials,and after cultivated paddy seedling until 3rd-leaf period ,set them in soil that contaminated by 10mg·kg-1, 20mg·kg-1, 40mg·kg-1 and 80mg·kg-1 Napand Phe soil (soil without Nap and Phe as control), and then determined the changes of physiological and biochemical indexes of seedlings under Nap and PHE stress at seedling stage, tillering stage and elongating stage respectively,and Nap and PHE residues after havesting. The results showed that:(1)Seedling stage:With increasing of Nap concentration,stem diameter and stem heigh and plant heigh of paddy seedlings represent that stimulated growth at lower concentration(lower than 20mg/kg),less than 30% of control,while restraining effects achieved 42.24% of control;With increasing of Phe,the trend of stem diameters were similar to that of Nap stress,but no remarkable differences between various concentration groups, moreover stem heigh and plant heigh of each concentration were lower markedly than the control,and less than 32% of control. Consequently,the effect of NAP on growth of paddy was greater than tha of Phe stress.When the concentration of Nap and Phe was 20 and 80mg/kg,the changes of each physiological and biochemical indexes were more evident.And that the effect of Phe on nitrogen metabolizability of paddy seedling was higher than that of NAP stress,but the effect of Phe on lipid peroxidation was more serious.(2) Tillering stage: When the concentration of Nap and Phe was 20 and 40mg/kg,the differences of the changes of each physiological and biochemical indexes were greater,of which the results were consistent with that of tillering numbers.There were outstanding influences on paddy at 20 mg/kg Phe,when content of proline,SOD activity and chlorophyll a/b of leaves achieved upmost value, yet the content of protein was least;under 40mg/kg Nap stress, content of proline,chlorophyll a/b and caroteniod content of leaves were least, but the content of the protein and the MDA were both highest.So the effect of Nap and Phe on growth of paddy at tillering stage was different.(3) Elongating stage: the effect of Phe on lipid peroxidation was still outstanding, especially more serious influens on content of praline,SOD activity and content of MDA,and the restraining action was greater under Phe stress, prominently represent that the content of praline was higher 9 times than the control and the highest content of MDA reached 23.39% of control,but restraining SOD activity reached 28.95% of control.(4)After a growth cycle of paddy ,Nap in soil was almost degradated ,yet the cumulation content was increased in root and seed of paddy,and the cumulation content in seed was higher than that of root,and found that the cumulation content of Nap in seed was most under 20mg/kg Nap,and 40mg/kg second.Consequently,the paddy grew in chronically contaminated soil may be suffered from the effect of PAHs,and paddy by themselves cumulating dissociated praline, enhancing SOD activity and the content of protein and so on physiological and biochemical adjustive mechanism , reduced the damage on themselves.Under chronically organic contaminated stress,paddy itself had formed definite endurance.The study provides some foundation of scientific theory for investigating endurance and adaption mechanism under organic contaminated stress from now on..