摘要:
以云烟97为材料,采用人工控制土壤含水量的方法设置了轻度和重度水分胁迫,研究烟草生长、光响应特性、叶绿素荧光及品质对水分胁迫的响应.结果表明:1)水分胁迫抑制烟草植株的生长.2)胁迫处理下净光合速率、气孔导度和蒸腾速率下降,但差异无统计学意义.重度水分胁迫下叶片胞间CO2浓度显著上升,这表明在干旱条件下,烟草叶片光合作用的抑制受到气孔与非气孔因素的双重影响.3)随水分胁迫程度增加,叶片光补偿点和暗呼吸速率逐渐上升而光饱和点和最大净光合速率则持续降低.4)胁迫的强度会在水分逐渐降低的时候不断增强,同时伴随的还有初始荧光的变化,呈现出先降后升的趋势,而最大荧光以及PSⅡ光化学效率(Fv/Fm)、光化学猝灭和实际光化学效率不断降低而非光化学猝灭不断增加.这表示光合器官在轻度水分胁迫时没有受到明显影响,而重度胁迫则造成PSⅡ反应中心破坏.5)水分胁迫处理后烟草化学成分发生改变,轻度水分胁迫的烟草品质协调性分值最高,达95.85,表明适当地进行烟草中的水分胁迫处理能够提高烟草品质.
关键词:
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烟草
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品质
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光合特性
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水分胁迫
Abstract:
In order to study the change of growth, light response, chlorophyll fluorescence and quality of tobacco ''Yunyan 97'' under different level water stress, mild and severe level of water stress has been set up, and has been carried out by manual control of the water content in soil.The results show that 1) water stress inhibited the growth of tobacco plant;2) the net photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (Tr) decreased under water stress but not significantly, and intercellular CO2 concentration (Ci) increased significantly under severe water stress, these results indicate that the inhibition of leaf photosynthesis were influenced by stoma and non-stoma factors under dry conditions;3) with the increase of water stress, the light compensation point (LCP) and dark respiration rate (Rd) risen gradually, but the light saturation point (LSP) and net photosynthesis rate (Pn) decreased by degrees;4) with the increase of water stress, the F0 firstly decreased and then increased and the Fm, Fv/Fm, qP and ΦPSⅡ decreased by degrees but qN increased gradually.These results indicated that photosynthetic organs was not affected during mild water stress but PSⅡ reaction center was destroyed by severe water stress treatment;5) The tobacco chemical composition were changed by water stress treatment and the highest score of tobacco quality reached 95.85 after mild water stress treatment, the result indicated that appropriate water stress treatment was benefit to improve the quality of tobacco.
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