植物营养与肥料学报2025，Vol.31Issue(12)：2415-2430,16.DOI:10.11674/zwyf.2025095
深层根系减少及氮利用不足引发常规滴灌和氮肥量下水稻颖花退化
Insufficient deep-root growth and nitrogen utilization under conventional drip irrigation and nitrogen application rates causes spikelet degeneration in rice
摘要
Abstract
[Objectives]Drip-irrigated rice demonstrates good water-saving potential and favorable yield performance.However,spikelet degeneration remains a major constraint,and the underlying mechanisms are note yet fully understood.In this study,we evaluated the impacts of water and nitrogen(N)management on root growth,N uptake and utilization,and yield formation in drip-irrigated rice.The findings would provide a theoretical basis for understanding spikelet degeneration and optimizing water-nitrogen strategies.[Methods]A split-plot field experiment was conducted during the 2022 and 2023 growing seasons.The main plots were assigned three irrigation regimes:continuous flooding(FI);conventional drip irrigation(DIO,maintaining soil moisture at≥90%of field capacity);and water-stressed drip irrigation(DIS,maintaining soil moisture at 80%-100%of field capacity).The subplots consisted of three N application levels:low(LN,N 240 kg/hm2),moderate(MN,N 300 kg/hm2),and high(HN,N 360 kg/hm2).At the early,middle,and late panicle differentiation stages(58,68,and 78 days after emergence,respectively),photosynthetic parameters were measured,and the above ground plant parts were sampled for analysis of biomass and nitrogen content,and the root growth was investigated in 0-50 cm soil profiles,segmented into 10 cm layers.At the late panicle differentiation stage(78 days after emergence),the primary and secondary panicle branches and the spikelet were sampled to investigate the degeneration rate.The grain yield was investigated at maturity.[Results]Compared with FI,DIO and DIS treatments exhibited 5.95%and 11.97%higher branch degeneration rates,respectively,with a rising trend in spikelet abortion rates,resulting in average grain yield reductions of 24.75%and 53.32%over the two-year period.During the panicle differentiation stage,the DIO treatment significantly reduced leaf N content,net photosynthetic rate(Pn),deep root biomass(10-50 cm),and partial factor productivity of nitrogen(PFPN)by 17.23%,13.44%,57.95%,and 28.03%,respectively,relative to FI.The DIS treatment caused even greater reductions of 24.56%,26.67%,65.01%,and 55.55%,respectively.Under the same irrigation regime,the HN treatment increased leaf Pn,leaf N content,and grain N content compared to MN,with a notable increase of 10.62%in leaf N content,whereas the LN treatment showed a decreasing trend.Deep root biomass under DIO and DIS was significantly lower than under FI.Increasing nitrogen input promoted deep root biomass and yield of rice while significantly reducing the degeneration rates of branches and florets.Partial Least Squares Path Modeling(PLS-PM)demonstrated that improved water-nitrogen management(increased nitrogen application and drip irrigation)enhanced the proportion of deep roots and nitrogen uptake efficiency,thereby improving Pn and PFPN,which in turn reduced panicle branch degeneration and spikelet abortion rates,and ultimately mitigated yield losses in drip-irrigated rice.[Conclusions]Drip irrigation promotes shallow root growth but reduces deep root biomass of rice.This shift in root architecture poses a risk of inefficient nitrogen utilization and constitutes a key factor leading to the degeneration of branches and spikelets.Increasing nitrogen fertilizer can enhance deep root biomass and nitrogen use efficiency,thereby mitigating spikelet degeneration in drip-irrigated rice,however,may lead to decreased nitrogen use efficiency.Further study is needed to regulate the drip irrigation and the distribution of rice root system in soil.关键词
水稻/滴灌/氮施用量/深层根系生长/光合速率/枝梗和颖花退化/产量Key words
rice/drip-irrigation/nitrogen application rate/deep-root growth/photosynthetic rate/branch and spikelet degeneration/yield引用本文复制引用
YANG Chang-nan,LI Juan-juan,CHENG Li-yang,LI Xiao-yan,LI Xiao-dong,YOU Ji-rong,ZHANG Xin-jiang,WEI Chang-zhou..深层根系减少及氮利用不足引发常规滴灌和氮肥量下水稻颖花退化[J].植物营养与肥料学报,2025,31(12):2415-2430,16.基金项目
兵团财政科技计划项目(2022ZD054) （2022ZD054）
国家自然科学基金(32060721) （32060721）
石河子大学青年创新拔尖人才计划项目(CXBJ202106). （CXBJ202106）
