水分胁迫对彩椒幼苗生长及光合特性的影响

以黄色彩椒花仙子幼苗为试材,研究了桶栽称重控水条件下水分胁迫对彩椒幼苗生长及光合特性的影响。结果表明:1随着水分胁迫时间的延长,彩椒幼苗株高、茎粗、叶片数和叶面积呈上升趋势,但随水分胁迫程度的增强,彩椒幼苗株高、茎粗、叶片数、叶面积、根长、根体积、地上部干鲜重和地下部干鲜重明显降低,而根冠比增大。2随着水分胁迫时间的延长,彩椒幼苗叶片的净光合速率(Pn)、气孔导度(Gs)、胞间CO2浓度(Ci)、蒸腾速率(Tr)、最小荧光(Fo)、暗适应下叶片PSⅡ的最大量子产额(Fv/Fm)和叶片PSⅡ潜在活性(Fv/Fo)均呈下降趋势,而叶片PSⅡ光合性能指数(PI)和叶绿素含量升高,但随水分胁迫程度的增强,幼苗叶片叶绿素含量、Pn、Gs、Ci、Tr、Fv/Fm、Fv/Fo和PI均明显下降,而Fo明显升高。3隶属函数分析结果显示,与彩椒幼苗受水分胁迫密切相关的生长指标为叶面积、根长、株高、根冠比和根体积;与光合指标密切相关的为Ci和Pn;与叶绿素荧光参数密切相关的指标为Fv/Fm、PI和Fo。轻度(75%的田间持水量)和中轻度(65%)水分胁迫对彩椒幼苗生长发育及光合特性影响较小。综合分析,75%~65%之间的田间持水量可以满足彩椒生长对水分的需求。

Effects of water stress on growth and photosynthetic characteristics of color pepper seedlings

The seedlings of yellow color pepper Huaxianzi were used to study the effects of water stress on their growth and photosynthetic characteristics . The results showed that with the extended duration of water stress , plant height ,stem diameter ,leaf number and leaf area were increased .With the increase of water-stress levels ,some growth indexes ,such as plant height , stem diameter , leaf number , leaf area , root length , etc ., became significantly de-creased ,whereas root-shoot ratio went increased .In addition ,with the increase of time under water stress ,some photo-synthetic indexes and fluorescence parameters including net photosynthetic rate ( Pn) ,stomatal conductance (Gs) ,in-tercellular CO2 concentration (Ci) ,transpiration rate (Tr) ,minimal fluorescence ( Fo) ,maximum number of PSⅡquantum yield ( Fv/Fm ) and leaf potential activity of PSⅡ ( Fv/Fo ) ,showed a downward trend ,but PSⅡ leaf photo-synthetic performance index (PI ) and chlorophyll content were increased .With the increase of water-stress degrees ,all photosynthetic indexes and fluorescence parameters became decreased significantly except for Fo .Moreover ,based on the subordinate function analysis ,some growth indexes such as leaf area ,root length ,plant height ,root-shoot ratio ,and root volume ,and some photosynthetic indexes and fluorescence parameters including Ci , Pn , Fv/Fm , PI and Fo ,were closely related with water-stress degrees in yellow color pepper seedlings .In conclusion ,75% and 65% of soil water ca-pacities had no effect on growth and photosynthetic characteristics of yellow color pepper seedlings ,which could meet wa-ter demand for the normal growth of yellow pepper .