土壤历史水分条件对干旱胁迫下辣椒生长及生理特性的影响

Effects of soil historical water content on the responses of pepper growth and physiological characteristics to drought stress

干旱严重制约农业生产,提高植物抗旱性是应对干旱灾害的现实需求。土壤抗旱遗产为提高植物抗旱性提供了新的思路。本研究以辣椒为对象,分别以超过50年种植历史的旱地和稻田土壤为基质进行盆栽试验,调节土壤水分为田间持水量的70%~80%、50%~60%和20%~30%,分别记为对照(CK)、轻度干旱胁迫(LD)和重度干旱胁迫(HD)。结果表明,干旱胁迫显著影响稻田土壤中辣椒的生长,辣椒的株高、叶面积、茎干重、叶干重、总生物量、叶绿素、类胡萝卜素含量均随干旱胁迫的加剧而降低。旱地土壤中辣椒的株高、叶面积、茎干重、根干重、叶干重和总生物量在轻度干旱胁迫下较对照呈增加趋势,增幅在15%~55%,但叶绿素和类胡萝卜素含量明显下降,降幅在15%~30%;重度胁迫条件下,上述形态指标相较于轻度胁迫明显降低,叶绿素和类胡萝卜素含量则略有增加。综上,栽培于旱地土壤基质的辣椒在轻度胁迫下能够较好地生长,这可能是由于旱地土壤长期的低水分环境降低了辣椒的水分需求,即提高了植物的抗旱性,但轻度干旱胁迫对辣椒的生理特征依然具有抑制作用。

Drought severely restricts agricultural production.Improving plant drought resistance is the practical needs,and soil drought resistance legacy provides a new idea to solve this problem.In this study,pepper was planted in two types of soil which had upland and paddy cultivation history more than 50 years,respectively.Soil moisture was adjusted to 70%~80%,50%~60%and 20%~30%of field water capacity,which was designated as control(CK)light drought stress(LD)and heavy drought stress(HD),respectively.The results showed that drought stress significantly affected the growth of pepper planted in paddy soils.The plant height,leaf area,stem dry weight,leaf dry weight,total biomass,chlorophyll and carotenoid contents strongly decreased as the rise of drought stress.However,the growth and physiological characteristics of pepper planted in upland soils showed a different trend to drought stress.The plant height,leaf area,stem dry weight,root dry weight and total biomass in LD significantly increased by 15%~55%compared with that in CK,whereas chlorophyll and carotenoid contents decreased by 15%~30%.In contrast,the above morphological indexes in HD decreased compared with that in LD,while chlorophyll and carotenoid contents significantly increased.In conclusion,pepper cultivated in upland soils grew well in light drought stress.The reason might be that long-term low water environment in upland soil induced drought resistance legacy,which improved the drought resistance of plants and reduced the water demand.However,physiological characteristics of pepper were inhibited under light drought stress.