ALA提高丙酯草醚胁迫下油菜幼苗耐性研究

对油菜幼苗叶面喷施不同浓度的丙酯草醚(ZJ0273)和5-氨基乙酰丙酸(ALA),研究了ALA与丙酯草醚协同处理对苗期的油菜是否安全。结果表明,丙酯草醚随浓度从100~1000mg/L变化,逐渐抑制油菜幼苗生长,鲜重减少,净光合速率和叶绿素含量降低;过氧化物酶(POD)、超氧化物歧化酶(SOD)和抗坏血酸过氧化物酶(APX)活性下降,丙二醛(MDA)积累提高。而10~100mg/L的ALA则促进油菜幼苗生长,增加植株的鲜重、净光合速率并提高了叶绿素含量,POD、SOD和APX酶活性均比对照显著提高,MDA积累减少;500mg/L的ALA效果相反,表现为抑制作物生长。100mg/L ALA和不同浓度的丙酯草醚协同处理,油菜幼苗均比对照生长的更好,鲜重增加,净光合速率提高,抗氧化酶活性增加,MDA积累减少。因此,ALA可以提高油菜幼苗在除草剂丙酯草醚胁迫下的耐性。

ALA IMPROVING Brassica napus SEEDLING TOLERANCE TO HERBICIDE STRESS

Complex combinations of new herbicide ZJ0273 propyl 4-(2-(4,6-dimethoxypyrimidin-2-yloxy)benzylamino)benzoate] and ALA(5-aminolevulinic acid) were used to investigate their combined effects in relation to seedling growth and development of oilseed rape(Brassica napus cv.ZS 758).It was found that ZJ0273 stress imposed negative effects on rape seedling growth.Net photosynthetic rates(Pn) were inhibited significantly under ZJ0273 stress and the rate of decline was consistently increased with the increase of ZJ0273 concentration.Chlorophyll contents were also inhibited significantly under ZJ0273 stress conditions and the higher concentration of the herbicide ZJ0273,the lower the chlorophyll content.Herbicide ZJ0273 treatment produced a gradual decrease in activities of antioxidant enzymes peroxidase(POD),superoxide dismutase(SOD) and ascorbate peroxidase(APX) and increase in accumulation of peroxidation substance malondialdehyde(MDA).The increase and decrease were consistent with the ZJ0273 dosages.Our results indicated that pre-and post-treatment with lower dosage of ALA(10-100mg/L) improved the rape seedling growth and net Pn rate while the higher concentration of ALA(500mg/L) depressed the growth.It was also found that the plant treated by 100 mg/L ALA produced the highest net Pn rate and chlorophyll content when the plants were treated with different concentrations of ZJ0273. Lower dosages of ALA improved the activities of antioxidant enzymes whereas the highest dosage of ALA increased the accumulation of MDA.These results indicate that ALA improves rape seedling tolerance to herbicide stress.