几种植物生长调节剂对春谷生长发育及产量的影响

Effect of Plant Growth Regulators on Growth and Yield of Spring Foxtail Millet

【目的】筛选出能有效降低春谷株高,提高其抗倒伏能力的植物生长调节剂及其最佳喷施期,并探讨不同药剂对春谷生长发育和产量的影响。【方法】分别于苗期、拔节期,对中晚熟区春谷(长生07)喷施5种植物生长调节剂(缩节胺、多效唑、赤霉酸、矮壮素、乙烯利),并设置清水对照(CK)。于灌浆期、成熟期测定各处理谷子叶绿素、光合速率、干物质积累量,以及主要农艺性状、产量等指标。【结果】(1)在春谷苗期和拔节期喷施矮壮素、多效唑、缩节胺3种药剂,都能不同程度地矮化植株,增加茎粗,调节次生根数和根重;提高叶片的叶绿素含量,增强光合效率。其中:苗期施用效果优于拔节期,并以矮壮素的效果最佳,与CK相比,苗期施用矮壮素处理的株高显著降低(-8.16%),茎粗(+6.67%)、次生根数量(+18.18%)和净光合效率(+16.07%)均显著增加(P<0.05),产量也有所增加(2016年+5.58%,2017年+5.67%)。多效唑的效果次之,与CK相比,在苗期、拔节期喷施多效唑,株高分别降低4.19%、2.24%,茎粗分别增加5.00%、3.21%,根重分别增加34.3%、30.4%(P<0.05)。缩节胺对株高和茎粗影响效果较为有限。(2)拔节期喷施乙烯利也能达到矮化和增产的效果,与CK相比,茎粗增加5.38%,次生根数增加21.21%,根重增加39.6%,穗干重和地上部干重均增加8.54%,差异均达显著水平(P<0.05),但叶绿素含量和净光合速率均降低。【结论】中晚熟区春谷可通过在苗期喷施多效唑、矮壮素,或于拔节期喷施乙烯利等措施,使现有品种株高降低、茎粗增加,从而适合机械栽培,并达到增强抗倒伏能力和增产目的。

【Objective】Various plant growth regulators(PGRs)capable of reducing plant height and improve lodging resistance without affecting crop yield were tested on the spring foxtail millet.Optimal spraying time of the selected agents were determined based on the effects on growth,development,and yield of the plants after the treatments.【Method】On the spring foxtail millet,Changsheng 07,at the seedling or jointing stage,5 PGRs for the treatment,as well as water as control,were sprayed separately.At booting and maturity stages,chlorophyll,photosynthetic rate,dry matters accumulation,major agronomic traits,and yield of the plants were measured for comparison.【Result】Among PGRs applied,chlormequat,paclobutrazol,and mepiquat chloride were found to dwarf the plants in varying degrees.The treatments increased the stem diameter,altered the secondary root number and weight,improved the lodging resistance,and increased the chlorophyll content and photosynthetic rate of the plants over control.Even the crop yield rose under the treatments as the plant tissues continued to propagate and accumulate at the booting stage.Spraying of the PGRs at seedling stage produced greater effects than at jointing stage,and the chlormequat application was more effective than the other PGRs.Compared to control,the treated plants were significantly shorter on height(decreased by 8.16%),larger in stem diameter(increased by 6.67%),more secondary roots with count increased(rose by 18.18%),greater net photosynthetic efficiency(higher by 16.07%)(P<0.05),and higher yield with 5.58%increase in 2016 and 5.67%in 2017.Less effective than chlormequat,paclobutrazol sprayed at seedling stage caused a plant height reduction of 4.19%,a stem girth enlargement of 5.00%,and a root weight increase of 34.3%,while at the jointing stages,those of 2.24%,3.21%,and 30.4%,respectively,in comparison to those of control.Among the three agents,mepiquat chloride was least effective in dwarfing the plant.After spraying at the seedling and jointing stages,the plant height decreased merely by 2.31%and 0.79%,respectively,while the stem thickness increased by 4.1%and 1.67%,respectively,over control.The application of ethephon at jointing stage also significantly dwarfed the plant with a 5.38%increase on stem thickness,21.21%increase on secondary root count,39.6%increase on root weight,8.54%increases on dry matters and aboveground plant weights,but significant decreases on chlorophyll content and net photosynthetic rate,over control.【Conclusion】The plant height and stem girth of the existing mid-and-late-maturing spring foxtail millet cultivars could be altered by spraying chlormequat or paclobutrazol at seedling stage or ethephon at jointing stage to facilitate mechanical cultivation,increase lodging resistance,and improve yield of the hay stock.