为探明除草剂对张杂谷10号安全性以及光合生理机制的影响,采用大田试验喷施不同剂量的苯磺隆和单嘧磺隆,于药后5、15和25d分别测定其光合特性等指标。结果表明:供试2种除草剂处理后,谷子叶片的光合色素含量、净光合速率(Pn)、气孔导度(Gs)、气孔限制值(Ls)、PSⅡ最大光化学效率(Fv/Fm)、PSⅡ潜在活性(Fv/Fo)、PSⅡ的有效量子产量(Y(Ⅱ))、电子传递速率(ETR)和光化学猝灭系数(qP)均有不同程度的降低,而胞间CO2浓度(Ci)和非光化学淬灭系数(NPQ)变化则呈现相反趋势,且均表现出一定的剂量-效应关系。此外,随着生育期的推进,各指标得到一定的恢复,进而谷子药害情况得到一定程度的缓解。除草剂引起的非气孔因素可能是张杂谷10号光合速率下降的主要原因,进而导致其PSⅡ反应中心的开放程度降低,活性减弱,光合电子传递受阻。谷子产量随供试除草剂喷施剂量的增加呈先增后降的趋势,苯磺隆显著影响了谷子各产量构成因素,而单嘧磺隆对穗粒重和千粒重影响效果最为显著。与对照相比,喷施推荐剂量的苯磺隆(225g/hm2)、单嘧磺隆(450g/hm2)对谷子造成一定的增产效果,且单嘧磺隆对张杂谷10号安全性较好,苯磺隆次之。
Field experiment was conducted to study the safety and photosynthetic physiological mechanism of herbicides on Zhangza Gu 10 by spraying different doses of Tribenuron-methyl and Monosulfuron.The photosynthetic indices were analyzed in 5,15,25 days after treamment.Results showed that after spraying two kinds of herbicides,photosynthetic pigment content,the photosynthetic rate(Pn),stomatal conductance(Gs),stomatal limitation value(Ls),PSII maximum quantum yield(Fv/Fm),potential photochemical efficiency of PSⅡ(Fv/Fo),PSII effective quantum yield(Y(Ⅱ)),electron transport rate(ETR)and photochemical quenching(qP)were all decreased.Intercellular CO2concentration(Ci)and non-photochemical quenching(NPQ)displayed remarkable dose-response.With the development of plant,all index were restored and phytotoxicity situation of millet recovered to some extent.It suggested that the non-stomatal limitation caused by herbicide may be the main reason for the decline of photosynthetic rate,which leaded to reduce the activity of PSⅡ reaction center,PSⅡ activity and photosynthetic electron transport.With the increase of herbicides,the yield tended to increase at first and then decreased.Tribenuron-methyl significantlyaffected the yield components and Monosulfuron grain affected the weight per ear and 1 000 grain weight significantly.Compared with the control,the appropriate dose of Tribenuron methyl and Monosulfuron Zhangza Gu 10 to be applied on Zhangza Gu 10 are 225g/hm2 and 450g/hm2 respectively and the latter is safer than the former.