摘要
以2个耐镉(Cd)性不同的甘蓝品种为材料,研究了不同Cd浓度(0、20、50、100μmol.L-1)对甘蓝植株生长、叶片光合特性和养分吸收的影响.结果表明:Cd敏感品种在低浓度Cd(20μmol.L-1)处理下生长受到明显抑制,叶片净光合速率(Pn)、气孔导度(Gs)、PSⅡ光化学效率(Fv/Fm)、PSⅡ光合电子传递量子效率(ΦPSⅡ)及地上部、根系干质量显著降低;Cd耐性品种在高浓度Cd(50和100μmol.L-1)处理下生长和光合特性受到显著影响;Cd胁迫降低了甘蓝叶片叶绿素a和b含量,尤其对叶绿素a的影响较大,进而抑制了叶片光合能力.Cd胁迫显著降低了植株对Mn的吸收,抑制了Mg和Fe从根部向地上部的转运,且Cd敏感品种受抑制幅度更大;Cd胁迫促进了Cd耐性品种对P和S的吸收,而Cd敏感品种相反.因此,Cd胁迫下甘蓝敏感品种叶片Mn、Fe、Mg、S和P含量的降低是影响其叶片光合作用,进而抑制植株生长的重要生理原因.
With solution culture, this paper studied the plant growth, photosynthetic characteristics and nutrient uptake of two cabbage （ Brassica oleracea L. ） cuhivars with different Cd-tolerance under treatments of 0, 20, 50 and 100 μmol Cd·L^-1. The results showed that the growth of Cd-sensitive cuhivar Qiufeng was inhibited obviously even under low Cd concentration （20 μmol·L^-1） stress. The net photosynthetic rate （Pn）, stomatal conductance （Gs） , photochemical efficiency of PSⅡ （ Fv/Fm ） and quantum yield of electron flow through PSⅡ （φPSⅡ） in its leaves and the dry weight of its shoots and roots declined sharply. However, negative impact on the synthetic characteristics of Cd-tolerant cuhivar Beino growth and photoeng was only observed under high Cd concentration （50 and 100 μmol·L^-1） stress. Cd stress decreased the contents of chlorophyll a and b, especially of chlorophyll b, which could be an important factor of photosynthesis inhibition. Under Cd stress, the Mn uptake by plant decreased significantly, and the transportation of Fe and Mg from roots to shoots was restrained, which were more obvious in Cd-sensitive than in Cd-tolerant cuhivar. Cd stress promoted the P and S uptake by Cd-tolerant cuhivar, but opposite results were observed in Cd-sensitive cuhivar. Therefore, physiologically, the decrease of Mn, Fe, Mg, S and P concentrations in Cd-sensitive cuhivar＇ s leaves under Cd stress was the key reason for the restraint of leaf photosynthesis, and the decrease of plant growth.
出处
《应用生态学报》
CAS
CSCD
北大核心
2007年第11期2605-2610,共6页
Chinese Journal of Applied Ecology
基金
国家自然科学基金项目(30571107)
南京农业大学青年创新基金资助项目(Y200620).
关键词
甘蓝
镉
叶绿素荧光
光合作用
养分吸收
cabbage （Brassica oleracea L. ）
cadmium （Cd）
chlorophyll fluorescence
photosynthesis
nutrient absorption
