| Aims:Rice cultivation by drip irrigation with plastic film mulch showed great water-saving and yield potential in practice.However,rice cultivation by drip irrigation with plastic film mulch suffered from iron deficiency stress at seedling stages in calcareous soil,some part of chlorotic rice die,which restricts rice cultivation by drip irrigation with plastic film mulch from extension.This paper aims to study on Fe efficiency in different rice genotypes under drip irrigation with plastic film mulch,physiological characteristics in different tolerant rice varieties to iron deficiency and effect of drought stress on iron efficiency in different tolerant rice varieties to iron deficiency.Methods:The research conducted at Xinjiang Tianye Agricultural Research Institute(field plot experiment),Agricultural Experiment Station in Shihezi University(pot culture experiment),Key Lab of Oasis Ecology Agriculture,Shihezi University(water culture experiment),Shihezi,Xinjiang province,China in 2015 and2016.In field plot experiment(2015),six rice varieties was choose in this study,single factor field trials was carried out,this experiment aims to select in different tolerant rice varieties to iron deficiency.In pot culture experiment(2016),two-factor was designed as rice genotypes(T-43,T-69 and T-04)and two iron fertilization way(without applying iron fertilizer and with applying iron fertilizer),aims to test physiological characteristics in different tolerant rice varieties to iron deficiency.In water culture experiment(2016),two-factor was designed as rice genotypes(T-43 and T-04)and three drought stress treatments(using polyethylene glycol(PEG6000)to simulate the drought stress,three treatments were set up,mass fraction PEG in nutrient solution was 0%,5%,10%,abbreviated CK,5%PEG and 10%PEG,respectively),aims to study effect of drought stress on iron efficiency in different tolerant rice varieties to iron deficiency.Results:1)Rice growth and yield had significant genotype differences under iron deficiency stress.Dry matter in shoot of T-201 and T-43 was significantly higher than other genotypes in seedling stage,but tiller number in T-201 was less than other genotypes.The dead number of tiller number inT-04 was more than other rice genotypes.Dry matter in shoot of T-43 was medium level in seedling stage and tillering stage,yield was higher in harvest stage.2)Iron efficiency had significant genotype differences under iron deficiency stress.Iron absorption capacity of T-43 and T-201 was significant higher than other genotypes in seedling stage and tillering stage.T-69 had higher ability of iron transfer than other genotypes in seedling stage.In tillering stage,iron accumulation in T-04 was accumulated in the stem and root mainly,iron accumulation in leaf of T-43 was significant higher than other rice genotypes.In addition,iron physiological utilization efficiency and leaf active iron in T-43 and T-X was higher.3)Root reductase activity of Fe-efficient genotype T-69 and T-43 was higher than Fe-inefficient genotype T-04,T-04 iron transfer and absorption ability was decreased under-Fe treatment.4)Iron concentration in shoot of Fe-efficient genotype of T-43 was higher than T-04 in drought stress treatment.In addition,rice root H+-ATPase activity was decreased and Fe-efficient genotype T-43 was higher than Fe-inefficient genotype T-04 under drought stress treatment.Root apoplast iron in T-43 was significantly higher in drought stress treatment than in CK treatment,T-04 was gradually reduced.Conclusions:1)Rice growth,yield and iron efficiency had significant genotype differences under iron deficiency stress.T-69 and T-43 were Fe-efficient genotypes,T-04 was Fe-inefficient genotype.2)By increasing the root reductase activity and root H+-ATPase activity under iron deficiency stress,Fe-efficient genotype of T-43 enhanced its root iron absorption capacity and iron transfer ability.3)Effect in Fe-efficient genotype of T-43 by drought stress was lower than Fe-inefficient genotype T-04. |
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