小麦初生根和次生根水肥利用效率及其与产量的关系

Use Efficiency of Both Irrigating Water and Nutrients between Seminal and Nodal Roots of Wheat(Triticum aestivum L.)and Their Relationship with Yield

为探究小麦初生根和次生根水肥利用能力的差异,于2021-2023年在河南省以主栽小麦品种周麦30和周麦32为材料,采用盆栽和分根移位的方法,设置初生根和次生根均灌水施肥(CK)、初生根不灌水(SRW_(0))、初生根不施肥(SRF_(0))、初生根不灌水不施肥(SRW_(0)F_(0))、次生根不灌水(NRW_(0))、次生根不施肥(NRF_(0))和次生根不灌水不施肥(NRW_(0)F_(0))7个处理,分别于越冬期、返青期、拔节期、开花期、灌浆期和成熟期分析初生根和次生根根系干物质量、根系活力、根系中氮磷钾素积累量的差异,并分析其对产量及其构成因素、籽粒中氮磷钾素积累量、氮磷钾素利用率和灌水利用率的影响。结果表明,分根水肥条件下,各处理的小麦单株初生根干物质量在越冬期均高于次生根,于开花期达到最大值;次生根干物质量在返青期以后均大于初生根,于灌浆期达到最大值。所有处理的各生育时期次生根根系活力始终高于初生根,初生根和次生根根系活力分别在返青期和拔节期达到最高值。分根水肥条件下,成熟期籽粒中磷素积累量及氮素和钾素利用率均表现为初生根水肥供应不足处理低于次生根水肥供应不足处理,即SRW_(0)<NRW_(0)、SRF_(0)<NRF_(0)和SRW_(0)F_(0)<NRW_(0)F_(0),而籽粒中氮素和钾素积累量及磷素利用率、籽粒产量及其构成因素、灌水利用率均表现为初生根水肥供应不足处理高于次生根水肥供应不足处理,即NRW_(0)<SRW_(0)、NRF_(0)<SRF_(0)和NRW_(0)F_(0)<SRW_(0)F_(0)。综合来看,小麦生育前期初生根生长发育强于次生根,而中、后期则弱于次生根;相同生育时期初生根的根系活力均低于次生根;初生根对磷素的吸收利用能力较强,而次生根则对氮素、钾素和水分的吸收利用更重要。

In this study,two main varieties Zhoumai 30 and Zhoumai 32 in Henan Province were used as materials from 2021 to 2023,and the differences of irrigating water and fertilizer use efficiency between seminal and nodal roots of wheat were investigated by pot cultivation experiments with root displacement method.A total of seven treatments were set up:designated as the seminal roots and nodal roots irrigated and fertilized separately(CK),no irrigation for seminal roots(SRW_(0)),no fertilization for seminal roots(SRF_(0)),no irrigation and fertilization for seminal roots(SRW_(0)F_(0)),no irrigation for nodal roots(NRW_(0)),no fertilization for nodal roots(NRF_(0)),and no irrigation and fertilization for nodal roots(NRW_(0)F_(0)).The root dry matter,root vigor,nitrogen,phosphorus and potassium accumulation in roots were analyzed at six growth stages,including overwintering stage,re-greening stage,jointing stage,anthesis stage,grain filling stage,and maturity stage.Yield and its components,nitrogen,phosphorus and potassium accumulation in grains,nitrogen,phosphorus,potassium and irrigating water use efficiency were investigated.The results showed that the dry matter of wheat seminal roots per plant was higher than that of nodal roots at overwintering stage,and that under all treatments reached the maximum value at anthesis stage.The dry matter of nodal roots was higher than that of the seminal roots after the re-greening stage,and all treatments reached the maximum value at the grain filling stage.The change trend of root vigor under each treatment showed that the vigor of nodal roots was always higher than that of seminal roots at different growth stages,and the root vigor of seminal roots and nodal roots reached the maximum value at re-greening stage and jointing stage under all treatments.Under the separate root irrigation and fertilization conditions,the phosphorus accumulation in grains and nitrogen and potassium use efficiency at maturity stage were lower in seminal root insufficient water and fertiilizer treatments than those in nodal root insufficient water and fertiilizer treatments(SRW_(0)<NRW_(0),SRF_(0)<NRF_(0),and SRW_(0)F_(0)<NRW_(0)F_(0)),while the nitrogen and potassium accumulation in grains and phosphorus use efficiency,the grain yield and its components,irrigating water use efficiency were higher in seminal root insufficent water and fertilizer treatments than those in nodal root insufficent water and fertilizer treatments(NRW_(0)<SRW_(0),NRF_(0)<SRF_(0),and NRW_(0)F_(0)<SRW_(0)F_(0)).The growth and development of seminal roots were better than those of nodal roots at the early growth stage of wheat,but weaker at the middle and late growth stages,while the root vigor of seminal roots was lower than that of nodal roots at different growth stages.The seminal roots were the main organ in phosphorus absorption and utilization,while the nodal roots was very important for the absorption and utilization of nitrogen,potassium and irrigating water.