| The corn acreage in Heilognjiang province pushed into first place.Also the province has high level of agricultural mechanization.Meanwhile,it can increase the corn yield by increasing the plant density suitably.But too much densities may lead lodging,it could destorys canopy structure,reduces photosynthesis and yirld.The aim of this study was to explore the impacts of KP(a kind of plant growth regulator which made by our lab)on maize stalk mechanical characteristics and yield.This research from 5 aspects to research and analysize.4 kinds of plant growth regulators(Yuhuangjin,Mi Gao,Duntianbao and KP)were sprayed on Dongnong 253 at the 9-leaf maize stage,and water as control.We study the stem mechanical properties,SOD,POD,CAT,MDA,soluble protein content in leafs,Photosynthetic Ezymatic Activities,Endogenous Hormone content of Dongnong 253 at the 10 days before tasseling stage(July 10),silking stage(July 22),initial filling stage(August 1),milk stage(August 25)and full maturity stage(September 25)respectively.At last measure yield and to analysis quality at harvest stage.The results indicate that:(1)The plant high,ear high and barycenter were decreased after treated.The effects of all treatment groups on plant high showed: KP > Yuhuangjin> Duntianbao>Mi Gao> CK,and the ear high showed: KP > Duntianbao> Mi Gao>Yuhuangjin> CK.Meanwhile,the dry weight per unit length,stems CSA,thickness,PSS,BSS and thrust have been enhanced.The stems oblateness has been reduced,so that the stems nearly circular.At last,improved lodgeresistance in the group.These phenomenon show that they are useful for transportation of water and nutrient.The KP has the most competitive one in treatment groups.(2)Autioxidant enzyme activities and soluble protein content increased and then decreased with the succession of the growing stages,and these indicators are greast at tasseling stage.The vary of MDA content was opposite to the varies of those.Compared with control,the autioxidant enzyme activities and soluble protein content increased but MDA declined after treatment.The KP has the most competitive one in treatment groups.(3)SPAD,PEPc,Ru BPc and Pn increased and then decreased with the succession of the growing stages,and these indicators are greast at tasseling stage.These indicators have been enhanced after treatment.The correlationanalys is showed that indicators above had positive correlation with yield.the contribution of the PEPc>Ru BPc at early stage but conversely at later stage.(4)At initial filling stage,the effect of 4 chemical groups on IAA,GA,and ZR in leaves showed that: KP>Yuhuangjin>Duntianbao >Mi Gao>KP;But decline of ABA in leaves showed that KP > Yuhuangjin> Duntianbao>Mi Gao> CK.At the same time,IAA in stems has been enhanced at all the five stages,GA and ABA at later stages had been reduced.The correlationanalys is showed that,the relationship of endogenous hormone content of leaves amoung 5 groups are GA>IAA>ZR>ABA.(5)The effects of plant growth regulators on the number of productive ear is not obvious,but Kernels per spike and 100-seed weight had improved significantly.The relationship of endogenous hormone content of leaves amoung 5 groups are KP(13159kg/ha)>Duntianbao(12828kg/ha)>Mi Gao(12826kg/ha)> Yuhuangjin(12744kg/ha)>CK(12047kg/ha).We found these plant growth regulators enforced dehydration in corn seeds at last stage.The experimental results show that Yuhuangjin proves the most obvious effect.The experiment show the validity of KP.All the indicators in this experimental are mutual compensation and mutual suppression simultaneously.These plant growth regulators could improve grain yield by enhance stem mechanical properties,osmotic adjustment system,photosyntheticand hormone indexes.This study could provide theoretical and experimental basis for thecultivation with plant growth regulator of maize in Heilongjiang province. |
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