【摘要】 为探讨不同钾水平对水分胁迫下甘蔗幼苗生理及光合特性的影响,采用水培及聚乙二醇(PEG6000)模拟水分胁迫处理的方法,在苗期设置2个钾浓度(3、0.05 mmol/L)和3种水分条件(非水分胁迫、轻度及中度水分胁迫)的组合处理进行研究。结果表明,随着水分胁迫强度的增加,正常供钾和低钾处理的甘蔗幼苗生物量、叶片净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)和叶片相对含水量(RWC)均下降,但正常供钾处理的下降幅度小于低钾处理;胞间CO2浓度(Ci)在正常钾处理下呈先升后降的趋势,而低钾处理下则相反;水分利用效率(WUE)、游离脯氨酸(Pro)及丙二醛(MDA)含量升高。在非水分胁迫下,与低钾处理相比,正常钾处理对甘蔗幼苗的生物量、叶片Pn、Gs、Tr和Pro含量影响甚微。但在水分胁迫下,正常供钾处理显著提高了甘蔗幼苗的生物量、叶片钾含量、Pn、Gs、Tr和Pro含量,抑制了MDA含量。上述结果说明适量施钾对甘蔗生长和光合能力具有明显促进作用,能有效缓解干旱胁迫对蔗株的伤害。更多还原

【Abstract】 By using the method of nutrient solution culture and simulated water stress with PEG6000, theeffects of two K treatments(3, 0.05 mmol/L) and three water conditions(non-water stress, mild and moderatewater stress condition) on physiological and photosynthetic characteristics of sugarcane shoots were studied.Results showed that with the rising of water stress, the biomass, leaf net photosynthetic rate(Pn), stomatalconductance(Gs), transpiration rate(Tr) and the leaf relative water content(RWC) of both the normal and thelow K treatments decreased, but the decrease range under the normal K supply was lower than that under thelow K supply. Intercellular CO2 concentration(Ci) went up first and then down under the normal K supply, butdeclined first and then increased under the low K supply. The water use efficiency(WUE), free proline(Pro)and malondiadehyde(MDA) contents increased with the rising of water stress. Under non-water stress, normalK supply had a little effect on the biomass, Pn, Gs, Tr and the content of Pro, compared with low K supply.Under the water stress, normal K supply increased the biomass, leaf K content, Pn, Gs, Tr and the content of Pro significantly, while reduced the accumulation of MDA. It indicated that normal K level could promote thegrowth and photosynthesis of sugarcane shoots and reduce the negative effect under drought stress.更多还原