土壤水分胁迫对茶树光合作用-光响应特性的影响

Effect of soil water stress on photosynthetic light response curve of tea plant (Camellia sinensis)

  • 摘要: 采用盆栽试验研究正常供水(土壤含水量为田间最大持水量的75%)、轻度水分胁迫(55%)、中度水分胁迫(35%)和重度水分胁迫(20%)条件下,茶树“铁观音”和“福鼎大白茶”2年生幼苗光合作用-光响应特性。结果表明:“铁观音”、“福鼎大白茶”光合作用-光响应曲线符合指数模型。在正常供水条件下,“铁观音”、“福鼎大白茶”的最大光合速率(Pnmax)分别为8.169 μmol(CO2-2·s-1、3.946 μmol(CO2)·m-2·s-1,表观量子效率(AQY)分别为0.039 μmol(CO2)·μmol-1、0.024 μmol(CO2)·μmol-1,光饱和点(LSP)分别为973.07 μmol·m-2·s-1、775.78 μmol·m-2·s-1,光补偿点(LCP)分别为5.15 μmol·m-2·s-1、6.49 μmol·m-2·s-1,暗呼吸速率(Rd)分别为1.025 μmol(CO2-2·s-1、1.040 μmol(CO2-2·s-1。土壤水分胁迫使“铁观音”、“福鼎大白茶”PnmaxAQY、LSP显著降低,而LCPRd提高。无论在正常供水还是在水分胁迫下,“铁观音”均表现出更高的光合活性,其PnPnmaxLSPAQY均比“福鼎大白茶”高,而Rd、LCP比“福鼎大白茶”低。表明生长在同一生境中的“铁观音”对光照、土壤水分的生态适应能力高于“福鼎大白茶”。

     

    Abstract: Two yearold seedlings of tea plants (Camellia sinensis cv. Tieguanyin and C.sinensis cv. Fudingdabaicha ) were cultivated in a pot experiment to investigate the photosynthetic parameters with light intensity of PAR 0 ~ 2 000 μmol·m-2·s-1 under four water stress treatments: 75% (normal water supply), 55% (slight water stress), 35% (mild water stress) and 20% (severe water stress) of soil field capacity. The results show that light response curves of net photosynthetic rate (Pn ) in “Tieguanyin” and “Fudingdabaicha” tea plants follow an exponential equation model. Under normal water supply condition, “Tieguanyin” and “Fudingdabaicha” maximum net photosynthetic rates (Pnmax) are 8.169 μmol(CO2)·m-2·s-1 and 3.946 μmol(CO2)·m-2·s-1; apparent quantum yields (AQY ) are 0.039 μmol(CO2)·μmol-1 and 0.024 μmol(CO2)·μmol-1; light saturation points (LSP ) are 973.07 μmol·m-2·s-1 and 775.78 μmol·m-2·s-1; light compensation points (LCP ) are 5.15 μmol·m-2·s-1 and 6.49 μmol·m-2·s-1; and dark respiration rates (Rd ) are 1.025 μmol(CO2)·m-2·s-1 and 1.040 μmol(CO2)·m-2·s-1 respectively. Under soil drought stress, Pnmax, AQY and LSP decrease while LCP and Rd increase. Compared with “Fudingdabaicha”, “Tieguanyin” presents higher Pn,Pnmax, LSP and AQY, but lower LCP andRd ; indicating that “Tieguanyin” has higher adaptation capacity to different soil water supply and light intensity than “Fudingdabaicha” under the same environmental conditions.

     

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