根际氧浓度对水稻分蘖期养分吸收和根系形态的影响

摘要

A hydroponic experiment was conducted to study the effects of rhizosphere oxygen concentration on rice seedling biomass,nutrient absorption and accumulation,and root morphology with Xiushui 09 and Chunyou 84 as material.With an online dissolved oxygen meter,four dissolved oxygen (DOTs )levels were set including low oxygen concentration(DOT 0 to 1 .0 mg/L),medium oxygen concentration(DOT 2.5 to 3.5 mg/L),high oxygen concentration (DOT >6 mg/L,continuous bubbling with atmospheric air)and control (conventional hydroponics,without oxygen regulation).The results showed that compared with the control,the root,shoot and total dry weights increased by 30.30%,32.96% and 32.46% for Xiushui 09 and by 7.01 %,1 .77% and 9.1 7% for Chunyou 84,respectively under the medium oxygen concentration;under high oxygen contentration,the root,shoot and total dry weights decreased by 35.35 %,1 5 .62% and 1 7.76% for Xiushui 09 and by 43.95 %,18.92% and 21 .34% for Chunyou 84,respectively.The root to shoot ratios increased under low oxygen treatment.The total absorption and accumulation of N,P,K,Mn,Mg and Ca increased under the medium oxygen treatment,and the total absorption and accumulation of Fe,Cu and Zn increased under the low oxygen treatment.The root tip numbers,length and surface area,the proportion of fine roots also increased and the coarse root decreased under the medium oxygen treatment.Under the medium oxygen treatment, the proportion of fine roots increased,which contributes to nutrient uptake.This might be one of the main reasons for the increase in some element concentrations.The biomass, nutrient concentration, and accumulation, and root morphology obviously varied with cultivar.%以秀水09和春优84为材料,利用在线溶氧仪(氧气、氮气调节)设置4个氧浓度(低氧,0~1 mg/L；中氧,2．5~3．5 mg/L；高氧,＞6 mg/L,即饱和溶解氧处理,在水稻生长过程中用充气泵连续向水体中充入空气；CK,常规水培,不进行氧调节),研究根际氧浓度对水稻幼苗生物量、养分吸收、积累以及根系形态的影响,探讨根际氧浓度变化情况下两个水稻品种幼苗养分吸收、积累和根系形态的差异.结果表明,与 O 2浓度正常水平(对照)相比,中氧处理增加两个水稻品种幼苗根系、茎叶和总生物量.秀水09分别增加30．30％、32．96％和32．46％；春优84分别增加7．01％、1.77％和9．17％；高氧处理减少两个水稻品种幼苗根系、茎叶和总生物量,秀水09分别减少35．35％、15．62％和17．76％；春优84分别减少43．95％,18．92％和21．34％.低氧处理增加供试品种的根冠比.中氧处理增加两个水稻品种的 N、P、K、Mn、Mg 和 Ca 的吸收累积总量,低氧处理增加其 Fe、Cu 和 Zn 的吸收累积总量.中氧处理增加两个供试品种幼苗根系总根长、表面积、总根尖数和细根比例,降低幼苗粗根比例,有利于水稻幼苗对养分的吸收,使部分营养元素含量增加.同时,中氧处理对水稻幼苗生物量、养分吸收、积累、分配和根系形态的影响存在显著品种差异.