Effects of Drought Stress on Key Enzymes of Carbon Metabolism, Photosynthetic Characteristics and Agronomic Traits of Soybean at the Flowering Stage under Different Soil Substrates

Soybean is an important legume food crop,and its seeds are rich in nutrients,providing humans and animals with edible oil and protein feed.However,soybean is sensitive to water requirements,and drought is an important factor limiting soybean yield and quality.This study used Heinong 84(drought resistant variety)and Hefeng 46(intermediate variety)as tested varieties planted in chernozem,albic,and black soils.The effects of drought stress on the activities of key enzymes in carbon metabolism and photosynthetic characteristics of soybean were studied during the flowering stage,most sensitive to water.(1)The activities of SS-1,6PGDH,and G6PDH enzymes in soybean leaves first increased and then decreased under drought stress.The enzyme activity was the highest under moderate drought stress and weakest in the blank group.(2)Drought stress increased Phi2,PhiNO,and Fm in soybean leaves and reached the highest value under severe drought;with the increase in drought stress,PhiNPQ and Fv/Fm of soybean leaves gradually decreased,reaching the lowest under severe drought.(3)With the increase in drought stress,F0 and Fs of soybean leaves showed a single peak curve,and the maximum was at moderate drought.(4)Correlation analysis showed that F0 was greatly affected by varieties and soil types;Fs,F0,and Fm soil varieties had a great influence,and chlorophyll fluorescence parameters were affected differently under drought stress with different drought degrees.(5)Drought stress changed the agronomic traits and yield of soybean.With the increase of drought degree,plant height,node number of main stem,effective pod number,100-seed weight and total yield decreased continuously.(6)Drought stress affected the dry matter accumulation of soybean.With the increase of drought degree,the dry matter accumulation gradually decreased.Among them,the leaf was most seriously affected by drought,and SD decreased by about 55%compared with CK.Under the condition of black soil,the dry matter accumulation of soybean was least affected by drought.

Effects of Different Herbicides on Weed Control,Agronomic Characters and Grain Quality of Coix lacryma-jobi L.

[Objectives]The paper was to study the effects of different herbicides on weed control,agronomic characters and grain quality of Coix lacryma-jobi L.[Methods]Six commonly used herbicides were selected for the trial,including atrazine SC,butachlor SC,monosulfuron WP,MCPA-starane EC,clopyralid AS and tribenuron-methyl WP.[Results](i)Atrazine,butachlor and monosulfuron had no chemical injury to C.lacryma-jobi L.,while clopyralid caused slight chemical injury.(ii)The fresh weight control effects of atrazine,butachlor and monosulfuron on weeds increased first and then decreased.The initial control effect of MCPA-starane and clopyralid reached more than 90%;the control effect of monosulfuron increased gradually in the late stage,reaching 97%at 60 d post spraying,and the overall control effect was optimal.(iii)Compared with manual weeding,herbicides had no significant effect on plant height of C.lacryma-jobi L.However,compared with no weeding,other herbicides except tribenuron-methyl inhibited plant growth to a certain extent.Herbicides had different effects on main stem diameter,tiller number per plant and grain number per plant of C.lacryma-jobi L.(iv)Different herbicides had no significant effect on 100-grain weight,but had significant effect on yield.(v)Compared with manual weeding,atrazine,butachlor and clopyralid decreased the protein content of C.lacryma-jobi L.,and the use of atrazine,butachlor,monosulfuron,MCPA-starane and tribenuron-methyl decreased the fat content of C.lacryma-jobi L.;butachlor and MCPA-starane decreased the glycerol trioleate content of C.lacryma-jobi L.Compared with no weeding,chemical herbicides had no significant effect on the protein content,while atrazine decreased the fat content,and butachlor and MCPA-starane decreased the glycerol trioleate content of C.lacryma-jobi L.[Conclusions]The use of herbicides significantly increases crop yield compared with no weeding,but has an impact on agronomic characters and grain quality.

Analysis on Heterosis and Combining Ability of Main Agronomic Characteristics in Huang-Huai-Hai Summer Soybean

With 10 elite soybean varieties from Huang-Huai-Hai Valleys as materials,25 hybridization combinations were compounded based on NC II,and the heterosis and combining ability for the major agronomic characters in summer soybean was studied.The results showed that heterosis of agronomic traits of soybean was ubiquity,and the average heterosis of all characters showed positive advantages.The advantage of seed weight per plant,number of seeds per plant and number of pods per plant were the highest,at 35.58%,34.23%and 31.47%,respectively,and thus made a great contribution to yield heterosis.The general combining ability of Hedou 19,Handou 6,Shanning 14 and Williams 82 was relatively higher in seed weight per plant,number of seeds per plant and number of pods per plant,and they are quality parents for designing strong hybridization combinations.There were significant differences in special combining ability(SCA)among parents for the same trait in different combinations.Some showed positive effect,and others showed negative effects.We should select the best combination according to breeding objective in selecting and matching special elite combinations.

Potential variability of trans-lysozyme gene rice under ecological conditions of Yunnan Province, China

Using trans-lysozyme gene rice line D2-1-2 and its restorer Zhonghua No.9 as test materials,we studied their agronomic characters and grain qualities under two ecological conditions of Yunnan Province.The results show that there were no significant differences in the agronomic characters between D2-1-2 and Zhonghua No.9,but the seed setting rate and plant height of D2-1-2 were significantly lower,while the protein,amino acid and mineral element(Ca,Fe and Zn in particular)contents in its crude grain were higher than those of Zhonghua No.9.It is suggested that there could be some potential genetic variances in the transgenic plant and the possibly induced environmental risk should be evaluated in multi-plots for several years.