不同盐浓度下硅对高羊茅苗期生长及光合特征的影响

摘要

坪用高羊茅(Festuca arundinacea)因长期多频灌溉往往生长在土壤盐渍化或潜在盐渍化的生境中,本研究采用盆栽试验分析了不同盐浓度下硅对两个高羊茅品种(抗性强的XD和抗性弱的K31)种子发芽、苗期生物量及光合特征的影响.结果表明,盐浓度、硅、品种、盐浓度×品种以及硅×盐浓度互作均显著影响了高羊茅种子发芽及苗期光合特征(P<0.05).两个品种XD和K31的出苗率、保苗率、生物量以及光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)、气孔限制值(Ls)均随盐浓度增加呈整体下降趋势,而胞间CO2浓度(Ci)随盐浓度增加整体呈上升趋势.硅在一定盐浓度范围内显著提高了XD和K31的出苗率、保苗率、生物量、Pn、Gs和Ls,而降低了Ci、Tr(P<0.05),且同一盐浓度下K31对硅响应的敏感性大于XD,这说明添加硅对盐生境下高羊茅生长的影响与品种自身抗性密切相关.%Tall fescue(Festuca arundinacea) frequently grows in saline soil, or in soil with a high potential for salinization due to long-term and frequent irrigation.A pot experiment was conducted to investigate the effect of Si on seed germination, biomass, and photosynthetic characteristics in stage two tall fescue seedlings under different salinization conditions.The results showed that seed germination, biomass, and photosynthetic characteristics of the seedlings was significantly affected by salt concentration, variety, silicon supply, interactions between salinization conditions and species, and interactions between silicon supply and salt concentrations.The seedling rate, the seedling survival rate, biomass, photosynthetic rate (Pn), transpiration rate (Tr), stomatal conductance (Gs), and stomatal limitation percentage (Ls) of K31 and XD tended to decrease with increase in salinity.Intercellular CO2 concentration (Ci) tended to increase with increase in salinity.Silicon significantly increased the seedling rate of XD and K31 and seedling survival rate and seedling biomass.Pn, Gs, and Ls decreased Ci and Tr under salinization conditions (P<0.05).The sensitivity of XD and K31 to silicon differed under the same salinization conditions.This indicated that the effects of silicon supply on tall fescue growth in saline conditions are closely related to resistance.