增施氮素对苗期渍水胁迫冬油菜生理特性及产量的调控效应

摘要

研究增施氮素对苗期渍水胁迫后冬油菜生理特性及产量的调控效应,可为冬油菜主产区渍水胁迫后植株生长恢复调控措施的选择提供重要参考.本研究采用盆栽和大田试验,在冬油菜5~6叶期设置渍水胁迫D0(0 d)、D6(6 d)和D9(9 d)三个处理,并在渍害胁迫解除后设置4个氮素增施水平N0(0 kg/hm2)、N2(30 kg/hm2)、N4(60 kg/hm2)、N6(90 kg/hm2),研究了增施氮素对苗期渍水胁迫后冬油菜的生理响应特性及产量的调控效应.结果表明:与单纯渍水不增施氮素相比,增施氮素均能有效改善冬油菜各项生理指标而提高产量,盆栽和大田试验各指标变化特征基本一致.增施氮素20 d后,随渍水胁迫天数的减少与氮素施用水平的增加,盆栽及大田植株叶片叶绿素含量、叶片和根系超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性以及产量增加,叶片和根系丙二醛(MDA)含量降低,除植株根系CAT活性以外,交互作用对其余各项生理指标及产量的影响均达到显著水平(P<0.05).与单纯渍水不增施氮素相比,盆栽及大田N4D6处理冬油菜叶绿素总含量、叶片和根系抗氧化酶活性以及产量均显著增加13.28%~26.98%(P<0.05),叶片和根系丙二醛含量显著降低20.24%~23.67%(P<0.05),除POD活性外,其余各指标均已恢复至自然对照水平;盆栽及大田N6D9处理叶绿素总含量、叶片和根系抗氧化酶活性以及产量均显著增加(P<0.05),叶片和根系MDA含量显著降低(P<0.05),但所有指标仍均未恢复至自然对照水平.因此,在冬油菜主产区苗期渍水胁迫6 d后增施纯氮60 kg/hm2以及渍水胁迫9 d后增施纯氮90 kg/hm2均能显著增强油菜渍水胁迫后的生理代谢活动,而提高作物产量.%The regulation of adding nitrogen on crop physiological properties and yield after waterlogging stress can provide valuable information for restoring crop growth. In this study, the method of combining field and pot experiments were adopted, including four adding nitrogen rates of 0, 30, 60 and 90 kg/hm2and three waterlogging time treatments of 0, 6 and 9 days. The results showed that compared with the treatment of only waterlogging stress but no adding nitrogen, adding nitrogen improved the physiological indexes and enhanced the yield, all the indexes had similar changing characters in both pot and field experiments. After 20 days from adding nitrogen, the chlorophyll contents in leaves, the activities of SOD, CAT and POD in leaves and roots, as well as the yield increased and the MDA contents in leaves and roots decreased while the waterlogging time decreased and the nitrogen rates increased, waterlogging time and nitrogen rates had significant interaction effects on the other physiological indexes and yield except the CAT activities in roots (P<0.05). Compared with the treatment of only waterlogging stress but no adding nitrogen, the chlorophyll contents in leaves, the activities of SOD, POD and CAT in leaves and roots, as well as the yield significantly increased from 13.28% to 26.98% (P<0.05), the MDA contents in leaves and roots significantly decreased 20.24% to 23.67% under the treatment with waterlogging lasted 6 days and applying N 60 kg/hm2 in both pot and field experiments (P<0.05), other indexes already restored to the level of the treatment of no waterlogging stress and adding nitrogen (CK) except the POD activities; The chlorophyll contents in leaves, the activities of SOD, POD and CAT in leaves and roots, as well as the yield significantly increased (P<0.05), the MDA contents in leaves and roots significantly decreased under the treatment with waterlogging lasted 9 days and applying N90 kg/hm2 in both pot and field experiments (P<0.05), but all the indexes could not restore to the level of CK. In the main planting region of winter rape, adding 60 kg/hm2 after 6 d waterlogging stress or 90 kg/hm2 nitrogen after 9 d waterlogging stress can restore and promote the plant growth and reduce the yield loss.