Effect of Coupling of Water and Nitrogen on Shoot and Root Growth and Water Use Efficiency of Cotton Seedlings
LI Wenrao
FAN Yulong
FENG Shizhen
WANG Huanfang
Abstract：Alternative partial root-zone irrigation(APRI) and conventional water supply(NI) were used to cultivate cotton seedling,coupling with different nitrogen levels(high nitrogen 200 kg/ha,medium nitrogen 120 kg/ha and low nitrogen 80 kg/ha),in order to estimate the feasibility of improving WUE after nitrogen application under water saving irrigation condition.The effects of growth,photosynthesis,root morphology,root and shoot biomass,instantaneous and biomass water use efficiency(WUEi and WUEb)and so on were measured.The results showed that drought stress significantly reduced the plant height,leaf area,photosynthetic parameters [including net photosynthetic rate(Pn),transpiration rate(Tr) and stomatal conductance(Gs)],water consumption by transpiration,root biomass and shoot biomass,but significantly increased the ratio of root to shoot,root length(including total root length and <2 mm fine root length) and root surface area in cotton seedlings.Drought stress,however,significantly increased WUEi and WUEb.Compared with medium nitrogen treatment,high nitrogen increased the plant height,stem diameter,leaf area,Pn,Tr,Gs,water consumption by transpiration and root/shoot biomass of cotton seedlings,at the same time,improved total root length and surface area of the roots,but decreased WUEi and did not change WUEb in NI treatment.Low nitrogen improved the inhibition of growth,photosynthesis and accumulation of root/shoot biomass induced by drought but increased WUEi and WUEb under drought stress.Compared with NI treatment,APRI increased the plant height,stem diameter,leaf area,Pn,Tr,Gs,root/shoot biomass,total root length and surface area,but decreased water consumption by transpiration.Therefore,APRI increased WUEi and WUEb in cotton seedlings.The combined treatment of APRI and nitrogen may improve adaptation of growth and root morphology to drought stress and then it will increase WUE.Although WUE is higher in APRI coupling with low nitrogen treatment,cotton seedlings growth is better in APRI coupling with high nitrogen treatment.
Keywords：cottondroughtalternative partial root-zone irrigationnitrogen application ratewater use efficiencyroot morphologyphotosynthetic parameters
Publication Date：2017-09-01
Online Publishing Date：2026-09-12(First online date of this platform, not the publication date of the document)
Pages：7( 18-24 )