尿素增强烯草酮胁迫下紫苏幼苗耐性的研究

为探讨烯草酮与尿素处理对紫苏生长的影响,阐明尿素对紫苏在烯草酮胁迫下耐性的调节效应。采用随机区组试验设计,在紫苏六叶期喷施不同浓度的尿素（0、1、2、4和 8 g/L）和24%烯草酮乳油（0、0.67、1.33、2.66和 3.99 mL/L）,分析其对紫苏生长、光合特性、抗逆性指标、杂草防效和产量的影响。结果表明,烯草酮抑制紫苏幼苗生长,降低光合特性,使丙二醛积累增加,超氧化物歧化酶、过氧化物酶活性随其浓度的增加呈先上升后下降趋势;而1～4 g/L浓度的尿素处理则促进生长,并提高了光合特性;8 g/L的尿素处理效果相反。1～4 g/L的尿素和不同浓度的烯草酮先后处理,比单施烯草酮处理的效果好,A组（先喷施尿素后喷施烯草酮）的C1N3（4 g/L尿素,0.67 ml/L烯草酮）处理可使现蕾期产量和子粒产量比单独施用烯草酮增产13.94 %和10.54 %,株防效提高11%。表明在紫苏六叶期先喷施4 g/L的尿素再喷施0.67 mL/L 的烯草酮,能显著提高紫苏幼苗在烯草酮胁迫下的耐性,提高幼苗净光合速率,促进植株生长,这些效应与其提高抗氧化酶活性有关;该施药模式具有提高防效,安全高产等特点,有较高的推广价值。

Improvement of the tolerance of Perilla frutescens(L.) Britt. seedlings to clethodim stress by urea

The effects of urea and clethodim on the growth,photosynthetic characteristic,resistance,weed control and yield of Perilla frutescens(L.) Britt.were studied by using the randomized block design experiment.Perilla frutescens(L.) Britt.seedlings at the six-leaf stage were treated with either different concentrations of urea(0,1,2,4 and 8 g/L) or 24% clethodim EC(0,0.67,1.33,2.66 and 3.99 mL/L) or their combinations.The results show that the seedling growth and photosynthetic characteristic are depressed,while the accumulation of malondialdehyde(MDA) is increased under the clethodim treatments.The activities of superoxide dismutase(SOD) and peroxidase(POD) are increased at first,and then decreased with the increase of clethodim level.The seedling growth and photosynthetic characteristic are improved under lower dosages of urea(1-4 g/L),but depressed under higher concentration of urea(8 g/L).Pre-and post-treatments with lower dosages of urea(1-4 g/L) and different concentrations of clethodim show better effects than the clethodim treatment without urea.Compared with the application of clethodim alone,the dry weight at the squaring stage,seed yield and weed control efficiency are increased as by 13.94%,10.54% and 11%,respectively under the application of 4 g/L urea in combination of later application of 0.67 mL/L clethodim.These results indicate that Perilla frutescens(L.) Britt.seedling tolerance to clethodim stress is increased effectively.The growth and net photosynthetic rate(Pn) are improved through the increase of antioxidant enzymes when treated by 4 g/L urea first and then by 0.67 mL/L clethodim.This combination of urea and clethodium could improve the weed control effect,promote Perilla frutescens(L.) Britt.seedling growth and crop production,and exhibit great potentials for practical application.