Development Of 1,2,4-Triazole Plant Growth Regulators And Its Mechanism

“Chemical Control Technology” is a new cultivation technology produced by multidisciplinary cross-cutting.It has the advantages of less dosage,high effect,simple operation and easy promotion in agricultural production,which can alleviate crop genetics,environmental constraints and increase crop yield.It plays a very positive role in improving quality and crop resistance.Therefore,under the conditions of increasing population,reduced cultivated land,and frequent environmental stresses,the chemical control technology has attracted people's attention because of its unique advantages and functions.Uniconazole and paclobutrazol,as triazole plant growth regulator,play a very important role in increasing yield,controlling length and resisting stress.Nevertheless,there are also many shortcomings in the application of uniconazole and paclobutrazol,including the sensitivity of the drug to cause phytotoxicity,alleviating the stress damage and delaying the growth process of the crop,and the soil residue,which has certain safety hazards to the animal.In order to improve the productivity of mung bean and continue to develop high activity,low toxicity,green and environmentally friendly triazole plant growth regulators,eleven 1,2,4-triazole derivatives were synthesized,and conducted biological evaluation with mung bean "Lufeng 5" variety.All target compounds were used to soak seeds with different concentrations(0?M,1?M,10?M,100?M,1000?M),cultured in dark at 22±2?,and the root length and lateral root number of mung bean were examined after 5 days of culture.Longer roots was observed with CGR3 treatment at the 100?M.At the same time,CGR3 was studied on the endogenous hormone balance,root growth kinetics of mung bean and oral toxicity evaluation.In order to expand the application of CGR3 in mung bean production,the effect of CGR3 on mung bean seed germination,seedling growth and development,increasing mung bean stress resistance and yield were investigated,and the conclusions were followed :Ten derivatives containing 1,2,4-triazole functional groups were designed and synthesized,9 of which were new compounds and were reported for the first time.All new compounds were characterized by NMR and HRMS techniques.Further structural confirmation was carried out on some compounds by infrared(IR)and X-single-crystal diffraction.All the identification results can reasonably explain the structural characteristics of the compound,which is consistent with the expected results,indicating that the conditions for selecting the synthesis and the structural characterization methods are reasonable and effective.The compound AP2 has different effects on the physiological effects of mung bean according to its growth-promoting effect and uniconazole.AP2 and CGR3 are homologues with similar structural features.100? M CGR3 treatment promoted the elongation growth of mung bean main root,and its root length increased by 43.4% compared with the control treatment,higher than AP2 and the other synthesized compounds.The effect of promoting the root elongation of CGR3 at the same concentration is close to that of the market regulator DTA-6.These results broaden the physiological activity of triazole growth regulators,and CGR3 belongs to plant growth promoters.Mung bean seedlings(after germinated for 48 h)were treated with 100 ?M CGR3,which regulated the changes of IAA,ABA and GA3 in roots,but had no effect on ZR.CGR3 treatment significantly increased the level of auxin in the roots of mung bean,and reached the maximum on the fourth day after treatment,which was 3.15 times of the control treatment.Compared with the control treatment,CGR3 treatment enhanced the accumulation of ABA in the roots of mung bean;in CGR3-treated roots,the gibberellin change is not a continuous,indicating a tendency to inhibition in early stage and promotion in late.Under the same treatment conditions,the root elongation of mung bean had the maximum after 72 h of CGR3 treatment,which was 21.6% higher than that of the control treatment.According to the oral and rat acute toxicological test results of mice,it can be preliminarily judged that the compound CGR3 belongs to oral and transdermal acute low toxicity substances.Acute oral test in mice: male LD50 was 4250 mg/kg,female was 2890 mg/kg;rat(male,female)acute percutaneous test: LD50>2000 mg/kg.Soaking seeds with 250 ?M CGR3 significantly increased the germination potential,germination rate,germination index and vigor index of mung bean seeds;50 mg/200 g CGR3 seed dressing significantly increased the plant height,plant biomass and root-shoot ratio of mung bean seedlings.It indicated that CGR3 could effectively regulate the seed germination and seedling growth and development of mung bean.50 mg/200 g CGR3 enhanced the chlorophyll content,photosynthetic electron transport ability,potential photochemical energy,primary electron transfer capacity of PS II reaction center and the distribution of photochemical energy in the seedling stage,indicating that CGR3 treatment is beneficial to the absorption of light energy by mung bean leaves.Delivery and utilization.In addition,CGR3 treatment at this concentration also increased stomatal conductance and transpiration rate of mung bean leaves,and decreased intercellular carbon dioxide concentration and stomatal conductance.These results indicate that CGR3 can effectively regulate the opening of mung bean leaf stomata and maintain good Permeability facilitates gas exchange while increasing the utilization of carbon dioxide concentration,ultimately increasing carbon assimilation capacity and net photosynthetic rate.Under moderate salt stress,250 ?M CGR3 treatment can effectively alleviate the inhibition of salt stress in root length,root volume,root surface area and biomass;reduced the content of malondialdehyde,superoxide anion and hydrogen peroxide in roots,and decreased by 33.1%,29.18% and 41.56% respectively compared to the salt stress.With CGR3-treated mung bean roots,the content of GSSG,As A and As A/DHA rata were increased by 16.25%,4.93% and 25.8%,and the contents of GSH,DHA and GSH/GSSG were reduced by 43.85%,8.7% and 35.06%,respectively,compared with salt stress treatment.Additionally,250 ?M CGR3 treatment increased the activity of GR,CAT,GST,POD and SOD antioxidant enzymes,among which GST activity increased by 4.26 times,GR,POD,SOD and CAT activities increased by 1.11,1.45,1.16 and 1.29 times respectively under moderate salt stress,and induced seven candidate stress responsive glutathione S-transferase gene up-regulated expression in mung bean,they are LOC106755414 p-GST,LOC106775403 p-GST-p A,LOC106761010 GST3 like,LOC106754873 p-GST,LOC106755029 p-GST,LOC106761043 GST 3 like,LOC106755411 GST.The above results indicate that the appropriate concentration of CGR3 under moderate salt stress can reduce the content of reactive oxygen species in mung bean roots and reduce the degree of cell membrane peroxidation,by enhancing glutathione-ascorbic acid cycle,antioxidant enzyme activity and glutathione.The up-regulated expression of the peptide thiol transferase-related gene ultimately increases the ability of mung bean to resist moderate salt stress damage.The initial flowering stage(R1)was sprayed with 100 mg/L of CGR3.Compared with the control,CGR3 treatment regulated the net photosynthetic rate,transpiration rate,stomatal conductance,intercellular carbon dioxide concentration and SPAD value of mung bean leaves.The maximum transpiration rate and SPAD value were obtained in the flowering stage(R2)at 100 mg/L,and the maximum transpiration rate,net photosynthetic rate and SPAD value were obtained in the R4 stage.The results of the results showed that 100 mg/L CGR3 could increase the number of pods per plant and the number of seeds per plant,which was 38.9% and 22.1% higher than the control treatment.The results of this study indicated that spraying 100 mg/L of CGR3 at the initial flowering stage(R1)enhanced the photosynthesis ability and yield of mung bean leaves,and increased yield by 23.4%.