【摘要】 为探讨铝胁迫对柑橘幼苗生物量累积及分配,光合特性[净光合速率（Pn）,蒸腾速率（Tr）,胞间二氧化碳浓度（Ci）和气孔导度（Gs）]和叶绿素荧光参数[初始荧光（F₀）,暗中最大荧光产量（Fm）,可变荧光（Fv）,最大光化学效率（Fv/Fm）和PSII潜在活性（Fv/F₀）]的影响,本研究以雪柑（Citrus sinensis）和沙田柚（Citrus grandis）实生苗为试验材料,采用砂培法设置不同浓度Al处理[0（对照）,0.5,1.0,2.0 mM Al Cl₃]以及不同Al处理时间[短期（15周）和长期（34周）]。研究结果表明,相比对照,短期2.0和0.5mM Al处理分别显著降低了雪柑和沙田柚幼苗的生物量且提高了雪柑和沙田柚幼苗的根冠比。长期0.5 mM Al处理显著降低了两柑橘品种幼苗生物量,提高了沙田柚幼苗的根冠比,但对雪柑幼苗无显著影响。无论是长期或短期Al处理,Pn,Tr,Gs,Fm,Fv,Fv/Fm和Fv/F₀均随Al浓度的升高而表现出下降趋势,Ci和F₀随Al浓度的升高呈上升趋势。综上,长期0.5 mMAl处理对两柑橘品种幼苗的抑制效果比短期处理更显著,柑橘幼苗铝毒害受胁迫浓度和胁迫时间共同调控。更多还原

【Abstract】 In order to investigate the effect of aluminum stress on growth and photosynthesis of citrus seedlings of aluminum( Al) toxicity on biomass accumulation and distribution, photosynthetic characteristics [ net photosynthetic rate(Pn),transpiration rate(Tr), intercellular CO2 concentration(Ci), and stomatal conductance(Gs)] and chlorophyll fluorescence parameters [the Initial fluorescence(F0),the maximum fluorescence(Fm),the variable fluorescence( Fv),the maximal photochemical efficiency( Fv/Fm) and the PSII potential activity( Fv/F0) ], sand culture was carried out in greenhouse using seedlings of Citrus sinensis and Citrus grandis. The seedlings were treated by nutrient solution plus four levels of Al [0(control), 0.5, 1.0, 2.0 mM] lasted either 15 weeks( short-term treatment) or 34 weeks( long-term treatment). The results indicated that Al stress had a negative effect on biomass accumulation of Citrus seedlings. Under short-term treatment, a significant difference of biomass inhibition was found in C.sinensis seedlings when exposed to 2.0 mMAl, whereas 0.5 and 1.0 mM Al resulted in insignificant difference of biomass reduction compared to control. For C.grandis seedlings under short-term treatment, significant downregulation on the biomass was observed when treated from 0.5 to 2.0 mM Al compared to control. Moreover, less reduction of biomassindicated a higher Al tolerance of C.sinensis seedlings than C.grandis seedlings. However, under long-term treatment with 0.5 mM Al, the seedlings’ biomass of two cultivars were depressed remarkably compared to 0 Al. The results supported that the hazardous effect from Al not only depended on Al level but also depend on the stress duration. The biomass distribution above and underground by Al stress was also analyzed and the results were expressed by the root/shoot ratio. In contrast to the tendency of biomass,the root/shoot ratio was increased significantly by 2.0 mM and 0.5 mM Al treatment in seedlings of C.sinensis and C.grandis by short-term treatment, respectively.An increasing tendency was maintained in C.grandis seedlings, however, no significant difference on root/shoot ratio of C.sinensis seedlings was found under long-term treatment. The biomass accumulation as well as the biomass distribution of Citrus seedlings under Al stress offered different strategies of Citrus species that in response to Al stress. Moreover, photosynthesis which resulted in carbon assimilation was also discussed by discussing the photosynthetic characteristic and chlorophyll fluorescence. It was shown that Al stress depressed the photosynthesis of two cultivars’ seedlings, for detail, the decreasing tendency of Pn,Tr,Gs, and increasing tendency of Ciwere found with Al levels up no matter under short or long-term Al treatment. By cultivar comparison, the seedlings of C.sinensis kept a higher Pn than seedlings of C.grandis under Al stress.For the chlorophyll fluorescence, anupregulated tendency of F0 and a depressed tendency of Fm,Fv,Fv/Fm and Fv/F0 was found with Al levels up both under short-term and long-term treatments. In conclusion,the inhibition on Citrus seedlings by 0.5 mM Al was more remarkable under long-term treatment compared to short-term treatment. The Citrus Al toxicity was regulated by both of stress level and stress duration. Higher Al tolerance of C.sinensis compared to C.grandis seedlings under Al stress would attribute to a higher solar utilization efficiency.更多还原