Effects Of Different Quantity Water-retaining Agent On Ecophysiological Characteristics Of Tobacco And Maize

Based on the research in physicochemical property of water-retaining agent carried out by our predecessors,we used nutritious drought resistance water-retaining agent as a new water saving chemical material in field experiment.Tobacco and maize as main experimental plants was used to perform a test in order to study the effects of different quantity of water-retaining agent on growth, development and ecophysiological characteristics of crops in field growing period.The study stages included root extending stage,fast-growing stage,maturity of tobacco and seedling stage of maize. The ecophysiological indices were mainly comprised of plant height,stem diameter,leaf number, leaf area,specific leaf area,relative water content,chlorophyll content,soluble sugars content, soluble protein content,proline content,MDA content,POD activity and root activity.In addition we recorded topsoil moisture content,temperature and humidity as environmental parameters.At last we comprehensively analyzed results to find out the optimal quantity of water-retaining agent,tried to interpret the ecophysiological adaptation mechanism of crops.The main conclusions were made as follows:1.The topsoil moisture content was improved observably by water-retaining agent in each growing stage.Along with increasing in quantity of water-retaining agent,topsoil moisture content was also increased.The tendency was obvious in long time interal after rainfall.A specified quantity of water-retaining agent provided a relatively steady soil moisture surroundings for crops growing,finally raised crops output.2.Compared with contrast,the optimal quantity of water-retaining agent increased evidently morphological index value included plant height,stem diameter,leaf number and leaf area.The yield didn't increase markedly by lower quantity of water-retaining agent.Tobacco and maize's growing was inhibited partly by higher quantity of water-retaining agent,but it still was good for plant growing.Considered with the economic factors,we choosed low cost quantity range in agricultural production.3.Tobacco and maize's physiological mechanism influenced significantly by a specified quantity of water-retaining agent.Tobacco's growth was boosted remarkably by a specified quantity of water-retaining agent.With increasing quantity of water-retaining agent,leaf relative water content,chlorophyll content,soluble sugars content,soluble protein content,root activity rised at first,lowered then and rised again at last,they peaked at the quantity of 30kg/hm~2,while the leaf proline content,MDA content showed the opposite pattern,it reached a minimum at the quantity of 30kg/hm~2.The change in leaf POD activity was similar with the change of proline.Tobacco root activity increased with higher quantity of water-retaining agent.At quantity of 30kg/hm~2, it got a peak which was very significantly different from CK(P＜0.01).After that point, root activity changed erratically with the increasing of water-retaining agent quantity. The variation tendency of specific leaf area in fast-growing stage and maturity was similar to the change trend in leaf relative water content,while it rised all the time until maximum at 60kg/hm~2 in root extending stage.The change in tobacco plant height,stem diameter,and leaf number per plant rised at first and lowered later,they reached the peak at 30kg/hm~2.With increasing quantity of water-retaining agent in seedling stage, maize's plant height,stem diameter,and leaf number per plant rised at first and lowered later,they reached the peak at 60kg/hm~2.The change of leaf chlorophyll content,soluble sugars content and soluble protein content rised at first,lowered then and rised again at last,they peaked at the quantity of 60kg/hm~2 and 120kg/hm~2,while the leaf proline content and peroxidase activity showed the opposite pattern,they reached a minimum at the quantity of 60kg/hm~2.4.During different growing periods of tobacco in field,the correlation analysis was made between morphological and physiological characteristics.The results showed that correlation was different in each growing stage of tobacco.Some correlation in characteristics index was higher and steady in one stage,the others were not.The correlation in morphological characteristics reached a peak in maturity.It got an evry significant level within characteristics(P＜0.05).The correlation in physiological characteristics have a big difference between each growth season and didn't show a regular performance.5.In the middle part of Henan,we used nutritious drought resistance water-retaining agent in field crop to against seasonal drought.It could improve soil texture conditions effectively,finally increased crops water using efficiency and production.The optimal quantity of water-retaining agent in tobacco growth was 30kg/hm~2(2kg per mu) and 60kg/hm~2(4kg per mu) in maize growth.