干旱胁迫下藜的光合特性研究

Photosynthetic Characteristics of Chenopodium album L.Grew under Drought-stress Condition

通过人工控制水分模拟干旱来研究生长期的藜对干旱胁迫的生理生化反应,以期望为干旱农业的高效生产提供理论依据。以盆栽的藜为材料,用称重控制浇水的方法,研究了干旱胁迫对藜叶片的光合特性。结果表明:干旱胁迫下藜的光合日变化呈双峰型,有"午休"现象(13:00)且受气孔限制;最大净光合速率出现在上午8:00。与正常条件下生长的藜相比,干旱胁迫下藜的光饱和点(LSP)、最大净光合速率(Pn)、表观量子效率(AQY)、二氧化碳饱和点(CSP)和羧化效率(CE)均降低,分别为1 200μmolphoton.m-2.s-1、8.01μmol CO2.m-2.s-1、0.016 1μmol CO2.mol-1photons、1 200μmol CO2.mol-1、0.017 6μmol CO2.m-2.s-1;光补偿点(LCP)、二氧化碳补偿点(CCP)升高,分别达到44.88μmol photon.m-2.s-1、和46μmol CO2.mol-1,干旱使藜的光合能力下降。干旱胁迫下藜的光合能力虽有所下降,但与其它C3植物相比仍具有较强的CO2同化能力。藜是一种耐旱力较强的植物。

Drought is one of the stress conditions that often severely effects plant growth. The loss of agricultural production due to drought stress is estimated to nearly equal the total losses caused by all other environmental stresses. In this study, the photosythetic parameter of Chenopodium album L. under artificially simulated drought stresses were examined to provide a theoretical basis for effectively increasing agricultural production in arid areas. C. album L. was grown from freshly harvested seeds under natural light. Six pots of plants showing similar growth was treated with drought stress by controlled irrigation： 15% water content of soil was kept by weighing, watered once two days for the entire experimental process; the pots were protected from exposure to rain. The photosythetic parameter of Chenopodium album L. was determined with LI-6400 Portable Photosynthesis System in the first ten-day of July. The result shows that the diurnal variation curve of photosynthesis in the leaves of C. album L. assumes was a two-peak pattern, had the middle-day depression and belongs to the stomatal limitation type under the drought stress condition. Its net photosynthetic rate（Pn） reached the peak value at about 8：00. Compared with the plant growing under normal condition, the photosynthetic light saturation point （LSP）, the net photosynthetic rate（Pn） , and carboxylation efficiency（CE） apparent quantum yield （AQY）, carbondioxide saturation point （CSP） all reduced, was 1 200 μmol photon · m^-2 · s^-1, 8.01 μmol photon ·m^-2 · s^-1 , 0. 016 1 μmol CO2 · mol^-1 photons,1 200μmol CO2 · mol^-1 and 0. 017 6μmol · m^-2 ·s^-1 respectively; However, light compensation point （LCP）, carbondioxide compensation Point（CCP） all increased,was 44.88 μmol photon · m^-2·s^-1 and 46 μmol CO2 · mol^-1 respectively. Under the drought stress condition,although the photosynthetic capability of C. album L. decreases, but comparing C. album L. with other C3-plant it still have a great capability of assimilation CO2. Chenopodium album L. is a drought-resistance plant.