磷胁迫对澳洲坚果幼苗叶片光合特性和荧光参数的影响

采用塑料管土柱法研究了磷胁迫对澳洲坚果幼苗叶片光合作用及叶绿素荧光特性的影响。结果表明:低磷CK(不施磷作为对照)、中磷MP(175 mg/kg P2O5)与高磷HP(350 mg/kg P2O5)之间有显著差异,澳洲坚果幼苗叶片的光合参数在低磷处理下净光合速率(Pn)、蒸腾速率(Tr)、胞间CO2浓度(C i)、气孔导度(Gs)均呈下降趋势,表明了供试的6个澳洲坚果品种(Hy、A16、863、951、695和Daddow)幼苗叶片光合能力随胁迫程度的加重均下降,叶绿素荧光参数中的最大荧光(Fm)、可变荧光(Fv)和最大荧光比(Fv/Fm)在低磷处理下也均降低,而初始荧光(F0)值升高。6个澳洲坚果品种之间有显著差异,根据测定参数对澳洲坚果各个品种幼苗的耐低磷能力进行综合评价,从强到弱依次为Daddow>951>695>A16>Hy>863。

Effects of phosphorus stress on photosynthetic characteristics and chlorophyll fluorescence of macadamia seedling leaves

Effects of phosphorus stress on photosynthetic characteristics and chlorophyll fluorescence of seeding leaves from six macadamia cultivars were studied with soil pole installation.The results showed that there was significant difference in photosynthetic capacity among the three phosphor treatments(CK,MP,HP).Under the low phosphorus condition,net photosynthetic rate,transpiration rate,intracellular concentration of CO2,stomatal conductance,maximum fluorescence,variable fluorescence and photochemical efficiency were significantly lower than those of the other two treatments except that minimal fluorescence increased remarkably.The results indicated that the photosynthetic capacity of seeding leaves from the six cultivars(Hy,A16,863,951,695 and Daddow) shown descending trend under the stress of low phosphorus.By evaluating low phosphorus tolerance,we concluded that there were significant differences among the six macadamia cultivars,and the low phosphorus tolerance of the seedlings from highest to lowest was ranked in order as: Daddow>951>695>A16>Hy>863.