【摘要】 采用营养液砂培试验,研究了不同浓度(0、1、3、5 mmol.L-1)Mg2+对红地球葡萄幼苗叶片叶绿体超微结构及光合响应的影响。结果表明,3 mmol.L-1 Mg2+处理的葡萄叶片叶绿体形状规则,富含大的淀粉粒,基粒、基质片层清晰;5 mmol.L-1处理的叶绿体结构没有发生明显的变化;而1 mmol.L-1和0 mmol.L-1处理的叶片叶绿体形状发生变化,叶绿体的被膜损坏,结构解体,基粒片层结构被破坏。不同水平Mg2+处理对叶绿素含量及光合作用参数也有显著的影响。0 mmol.L-1处理的叶绿素a(Chla)、叶绿素b(Chlb)、叶绿素(a+b)(Chl(a+b))、光饱和点(LSP)、最大净光合速率(Pnmax)、表观量子效率(AQY)、羧化效率(CE)均显著低于施镁处理,且随Mg2+浓度增大呈先上升后下降的趋势,叶绿素a/叶绿素b(Chla/Chlb)、光补偿点(LCP)、CO2补偿点(CCP)、CO2饱和点(CSP)变化趋势相反,3 mmol.L-1 Mg2+处理时最高。因此,在Mg2+缺乏的情况下,葡萄叶片叶绿体结构发生变异,叶绿素及碳代谢受阻,叶绿素含量及光合作用效率降低,而适宜的Mg2+浓度可提高葡萄对光和CO2的利用能力。更多还原

【Abstract】 Chloroplast ultrastructure and photosynthetic response of Red Globe grape(Vitis vinifera L.cv.) leaves were studied under different concentrations of Mg2+(0 mmol·L-1,1 mmol·L-1,3 mmol·L-1,5 mmol·L-1)with sandy culture method.The results indicated that in the treatment of 3 mmol·L-1 Mg2+,the chloroplast had normal shape,containing lots of big starch grains,and the structures of grana and stroma were clear.No obvious change of the chloroplast ultrastructure in the 5 mmol·L-1 treatment was observed,while in the 0 mmol·L-1 and 1 mmol·L-1 treatment,a series of chloroplast configuration changed,and the structures of granum and stroma lamellae were destroyed.Additionally,the concentration of magnesium significantly affected chlorophyll content and photosynthetic parameters.The contents of chlorophyll a(Chla),chlorophyll b(Chlb) and total chlorophyll(Chl(a+b)),the light saturation point(LSP),the maximum net photosynthetic rate(Pnmax),apparent quantum yield(AQY) and carboxylation efficiency(CE) were significantly lower in the 0 mmol·L-1 Mg2+ treatment than in magnesium treatments,and they increased and then declined with the increase of magnesium concentration.The change tendency of the ratio of Chl a/Chl b,light compensation point(LCP),CO2 compensation points(CCP) and CO2 saturation point(CSP) was opposite.The turn point of increase or decrease was at the treatment of Mg2+ 3 mmol·L-1.Therefore,the ultrastructure of chloroplast was aberrant,the metabolism of chlorophyll and carbon was inhibited and in turn chlorophyll content and photosynthetic efficiency reduced under Mg2+ deficiency while suitable magnesium concentration could improve the light and CO2 utilization ability of grape.更多还原