水氮耦合对郑麦9023结实期根系生理特性及产量的影响

以郑麦9023为材料,设置三个氮肥水平和两个水分处理来探讨水氮耦合下小麦根系生理特性差异及对产量的影响。结果表明:花后7~21 d,在同一水分条件下,随着施氮量的增加,根系活性、总吸收面积、活跃吸收面积及根系分泌的有机酸总量随着施氮量的增加呈先增加后降低的趋势,与200 kg·hm~(-2)(N2)相比,300 kg·hm~(-2)(N3)处理根系活性、总吸收面积、活跃吸收面积及有机酸总量分别降低了13.5%,9.0%,8.2%及20.9%;在同一氮肥水平下,与对照(-25 k Pa)相比较,水分胁迫(-60 k Pa)处理后根系总吸收面积、活跃吸收面积及有机酸总量有所增加,N3处理尤为明显。产量方面:在同一水分条件下,随施氮量的增加,小麦产量呈先增加后降低的趋势,与N1(0 kg·hm~(-2))处理相比,N2处理小麦产量平均提高72.1%,N3提高了61.4%,而N3处理比N2处理平均下降了6.6%;在同一氮肥处理下,水分胁迫后小麦产量有所增加。相关分析表明结实期根系活性、总吸收面积、活跃吸收面积及有机酸总量与产量呈显著及极显著正相关关系。说明灌浆期适度水分胁迫及N2条件下根系生理活性较强,更有利于产量的形成。

Effects of water and nitrogen interaction on root characteristics and yield of Zhengmai 9023 during grain filling stage

The purpose of this study was to investigate leaf senescence and yield differences by three nitrogen levels and two water treatments during grain filling stage under the condition of nitrogen and water coupling .A winter wheat cultivar Zhengmai 9023 was grown in the field .Root activity ,total absorbing surface area ,activity absorbing surface area and total organic acid in root ,as well as yield ,were measured at 7 and 21 day after flowing stage .The results showed that root physiological indexes ,such as root activity ,total absorbing surface area ,activity absorbing surface area and to-tal organic acid content ,were increased first and became decreased later with the increase of nitrogen application amount . Compared the treatment with 200 kg·hm-2 (N2 ) ,root physiological indexes including Root activity ,total absorbing sur-face area ,activity absorbing surface area and total organic acid content by 300 kg·hm-2 (N3) treatment were decreased by 13 .5% ,9 .0% ,8 .2% and 20 .9% .Compared with the control (-25 kPa) ,total absorbing surface area ,activity absorbing surface area and total organic acid content in root became increased under -60 kPa water stress when nitrogen level remains the same .In particular ,the effect was very predominant by N3 treatment .For yield ,under the same water treatment ,with the increase of nitrogen application ,wheat yield went increased first and then became decreased .Com-pared with N1 treatment ,wheat yields were increased by 72 .1% and 61 .4% by N2 and N3 ,respectively .Yield by N3 treatment was 6 .6% lower than that by N2 .With the same nitrogen fertilization ,wheat production after water stress was improved ,which was nevertheless significantly different from the control .Correlation analysis showed that there were sig-nificantly and extremely significant positive correlations between root activity ,absorption surface area ,total organic acid content and the yield ,indicating that root physiological activity is enhanced by proper water stress during wheat filling stage and N2 .The production can be facilitated thereby .