土壤水分时间变异性对糜子拔节期水分利用效率的影响

Effect of Temporal Soil Water Fluctuation on Water Use Efficiency of Broomcorn Millet(Panicum miliaceum L.)at Jointing Stage

【目的】探究土壤水分时间变异性对作物水分利用效率的影响。【方法】以糜子为研究对象,采用盆栽试验,设置4个处理,分别为稳定性高含水率(SW1)处理、稳定性低含水率(SW2)处理、波动性高含水率(FW1)处理和波动性低含水率(FW2)处理,分析不同处理对糜子生长发育、光合作用、气孔特征、生物量分配和生理指标的影响。【结果】(1)与波动性土壤水分(FW)处理相比,稳定性土壤水分(SW)处理显著促进了糜子拔节期生长。在控水60d以后,稳定性高土壤含水率(SW1)处理糜子株高、茎粗和叶面积分别较波动性高土壤含水率(FW1)处理提高了33.00%、13.04%和127.36%,稳定性低土壤含水率(SW2)处理糜子株高、茎粗和叶面积分别比波动性低土壤含水率(FW2)处理提高了51.94%、144.70%和13.91%。(2)SW处理更有利于糜子拔节期的光合作用、生物量积累和水分利用效率的提高。控水期间,SW处理糜子叶片净光合速率均显著高于FW处理;SW1处理鲜质量、水分利用效率分别比FW1处理提高了222.45%和200.00%,SW2处理鲜质量、水分利用效率分别比FW2处理提高了352.54%和260.00%。(3)SW处理显著增加了糜子拔节期叶片气孔的长度和宽度,降低了气孔密度。根丙二醛(MDA)、根抗氧化性酶(SOD、POD、CAT)、叶丙二醛(MDA)、叶脯氨酸(Pro)、叶超氧化物歧化酶(SOD)量和叶过氧化氢酶(CAT)量在各处理间无明显差异,根脯氨酸(Pro)、叶过氧化物酶(POD)、叶脱落酸量在SW1处理和FW1处理间差异显著。【结论】糜子对稳定性土壤水分和波动性土壤水分的响应不同,稳定性土壤水分条件更有利于糜子拔节期的生长发育、光合作用和水分利用效率的提高。

【Objective】Soil water in the field experiences spatiotemporal variation due to irrigation and rainfall evens,but its impact on crop growth is unclear.Using millet as a model plant,this paper investigates the effect of temporal soil moisture fluction on its water use efficiency.【Method】Experiments were conducted in pots with two soil water treatments:keeping the soil water content stable(SW),or temporally fluctuating it(FW).The former was achieved by keeping the pressure of irrigation water negative(NPI),and the latter by manual irrigation.In both treatments,the average soil water content was kept at 24.94%~25.61%(W1)or 21.12%~22.60%.The changes in growth,photosynthesis,stomatal characteristics,biomass allocation and physiological traits of the millet were measured in each treatment.【Result】①Keeping soil water content stable significantly promoted crop growth.60 days after start of the experiment,keeping soil water content stable in the range of 24.94%~25.61%(SW1)increased plant height,stem diameter and leaf area by 33.0%,13.04%and 127.36%,respectively,compared to FW1,while SW2 increased plant height,stem diameter and leaf area by 51.94%,144.70%and 13.91%,respectively,compared to FW2.②Compared to FW,SW increased photosynthesis,dry matter accumulation and water use efficiency.During the experimental period,the photosynthetic traits of the millet in SW were significantly higher than those in FW.③In addition,SW1 increased fresh biomass and water use efficiency by 222.45%and 200.00%,respectively,compared to FW1,while SW2 increased the fresh biomass and water use efficiency by 352.54%and 260.00%,respectively,compared to FW2.On average,SW increased length and width of leaf stomata while reducing leaf stomatal density.SW and FW treatments did not show significant influence on root malondialdehyde(MDA),root antioxidant enzymes(SOD,POD,CAT),leaf malondialdehyde(MDA),leaf proline(Pro),leaf superoxide dismutase(SOD)and leaf catalase(CAT)contents,but impacted root pro,leaf POD and leaf abscisic acid contents significantly.【Conclusion】The broomcorn millet responded differently to stable and fluctuating soil water content,with stable soil water content being more favorable to growth,photosynthesis and water use efficiency of the crop.