摘要
[目的]探究外源CaCl2对盐碱胁迫下万寿菊生长和光合特性的影响,为应用CaCl2提高盐碱地上万寿菊栽培效率和产品品质提供理论支撑.[方法]以万寿菊幼苗为试材,设置浇灌清水(CK1)、根灌80 mmol/L混合盐碱溶液(CK2)和根灌盐碱后叶面喷施4种浓度CaCl2溶液处理(5,10,15,20 mmol/L)进行盆栽试验,观测植株生长表型、叶片光合色素含量、光合气体交换参数和叶绿素荧光参数.[结果]随着盐碱胁迫时间延长,万寿菊植株的株高、茎粗、根系构型和根冠比呈逐渐上升趋势,叶片净光合速率(Pn)、蒸腾系数(Tr)、气孔导度(Gs)、叶绿素总量(Chl t)和最大光化学效率(Fv/Fm)等均呈下降趋势,而胞间CO2浓度(Ci)呈上升趋势,但这些指标在叶面喷施不同浓度CaCl2后变化幅度均有所降低,并均以10 mmol/L CaCl2处理效果最佳.在胁迫第20天时,10 mmol/L CaCl2 处理叶片 Chl t、Pn、T r、Gs、Fv/Fm 分别比 CK2 显著升高 46.78％、45.53％、49.51％、49.57％和 32.83％,其根冠比和Ci则分别显著降低22.60％和30.91％.[结论]叶面喷施10 mmol/L CaCl2可显著减轻盐碱胁迫下万寿菊叶片叶绿素含量降幅,提高PSⅡ的电子传递速率,增强叶片的光合能力,有效改善植株生长.
Abstract
[Objective]This study aims to explore the effects of exogenous CaCl2 on the growth and photo-synthetic characteristics of marigold(Tagetes erecta L.)under saline-alkali stress,and to provide theoret-ical support for the application of CaCl2 to improve the cultivation efficiency and product quality of mari-gold on saline-alkali land.[Methods]Taking marigold seedlings as test materials,pot experiment was car-ried out to observe the growth phenotype,photosynthetic pigment content,photosynthetic gas exchange parameters,and chlorophyll fluorescence parameters of marigold seedlings by watering(CK1),root irriga-tion with 80 mmol/L mixed saline-alkali solution(CK2),and root irrigation with saline-alkali followed by foliar spraying with four concentrations of CaCl2 solution(5,10,15,20 mmol/L].[Results]With the prolongation of saline-alkali stress,the plant height,stem diameter,root configuration,and root-shoot ra-tio of marigold plants showed a gradual upward trend,and the net photosynthetic rate(Pn),transpiration coefficient(Tr),stomatal conductance(Gs),total chlorophyll content(Chl t),and maximum photo-chemical efficiency(Fv/Fm)of leaves showed a downward trend,while intercellular CO2 concentration(Ci)showed an upward trend.After spraying different concentrations of CaCl2 on the leaves,the change of each index was decreased.There was a concentration effect,and the effect of 10 mmol/L CaCl2 treat-ment was the best.On the 20 th day of stress,the Chl t,Pn,Tr,Gs,and Fv/Fm of leaves treated with 10 mmol/L CaCl2 were higher than those of CK2 by 46.78％,45.53％,49.51％,49.57％,and 32.83％,while the root-shoot ratio and Ci were reduced by 22.60％and 30.91％,respectively.[Conclusion]Spra-ying 10 mmol/L CaCl2 on the leaves reduces the decrease of chlorophyll contents in marigold leaves under saline-alkali stress,increases the electron transport rate of PS Ⅱ,enhances the photosynthetic capacity of leaves,and effectively improves the growth of plants.
维普
万方数据