Abstract

Efficient selection for salt tolerance using the choice of physiological traits is of great importance. In the present study, seven ecotypes of Panicum antidotale (four from the Cholistan Desert and three from the non-Cholistani area) were evaluated after three weeks of salt stress. Results showed that shoot fresh biomass decreased by 74 and 83% respectively in Cholistani, and non-Cholistani ecotypes under salt-stressed conditions compared to control. Ecotypes from the Cholistan were more salt-tolerant (average dry biomass, 4.02 g) than non-Cholistani ones (average dry biomass, 3.14 g). Averaged across the Cholistani and non-Cholistani ecotypes, Cholistani ecotypes accumulated lower Na⁺ (72%) and/or higher K⁺ (179%) concentrations in their leaves than non-Cholistani ecotypes. However, parallels between the degree of salt sensitivity and relative water content, leaf water potential, leaf osmotic potential, and leaf turgor potential could not be generalized. In Cholistani ecotypes under salt stress, the total soluble protein on average was higher (11.51%) compared to non-Cholistani ecotypes (8.5%). Chlorophyll a decreased (0–20%) in all populations due to salt stress and it was positively associated with solar energy absorption and electron transport but could not be used to discriminate the populations. Chlorophyll fluorescence data indicated that salt stress damaged PSII functionality and electron transport further than Q_A⁻. The effective quantum yield of PSII, performance index, antenna size, energy flux for electron transport, rate of PSII reaction center closure positively correlated with salt tolerance of P. antidotale.

摘要

使用生理性状的选择来有效选择耐盐性非常重要。在本研究中，盐胁迫三周后评估了七种Panicum antidotale生态型（四种来自 Cholistan 沙漠，三种来自非 Cholistani 地区）。结果表明，与对照相比，在盐胁迫条件下，Cholistani 和非 Cholistani 生态型的枝条新鲜生物量分别减少了 74% 和 83%。Cholistan 的生态型比非 Cholistan 的生态型（平均干生物量，3.14 g）更耐盐（平均干生物量，4.02 g）。在 Cholistani 和非 Cholistani 生态型中平均，Cholistani 生态型累积较低的 Na ⁺ (72%) 和/或较高的 K ⁺(179%) 在叶子中的浓度高于非 Cholistani 生态型。然而，盐敏感性程度与相对含水量、叶片水势、叶片渗透势和叶片膨压势之间的相似性不能一概而论。在盐胁迫下的 Cholistani 生态型中，与非 Cholistani 生态型 (8.5%) 相比，总可溶性蛋白平均更高 (11.51%)。由于盐胁迫，所有人群中的叶绿素a降低（0-20%），它与太阳能吸收和电子传输呈正相关，但不能用于区分人群。叶绿素荧光数据表明盐胁迫对 PSII 功能和电子传输的损害比 Q _A ^-. PSII的有效量子产率、性能指标、天线尺寸、电子传输能量通量、PSII反应中心闭合率与解毒假单胞菌的耐盐性呈正相关。