干旱胁迫下香蕉幼苗光合生理特性变化

测定3品种香蕉幼苗在不同干旱胁迫下叶片色彩值、叶绿素含量、净光合速率（Pn）、蒸腾速率（Tr）、气孔导度（Gs）和胞间CO2浓度（Ci）等光合生理指标的变化。结果表明：3品种香蕉幼苗3个胁迫处理1 d后的L值、a值和b值与0 d相比均有所下降;巴西蕉和帝王蕉叶绿素含量轻度和中度胁迫时分别比对照显著降低14.9%和30.4%、29.7%和45.3%,重度胁迫分别比对照高12.8%和2.3%,而粉蕉叶绿素含量3个胁迫处理均显著低于对照;3种香蕉幼苗叶片色彩值与叶绿素含量不呈简单线性关系;随着胁迫程度的增加3品种香蕉幼苗的Pn、Tr和Gs均呈显著下降趋势,其中巴西蕉Pn降幅较大,分别降低80.1%、83.4%和92.4%,而3个品种Ci均显著高于对照。得出3个香蕉品种抗旱性顺序为粉蕉〉帝王蕉〉巴西蕉。

Changes in Seedling Photosynthetic Physiology Characteristics of Musa Varieties Under Drought Stress

Changes in photosynthetic physiological indices including chromatic value,content of chlorophyll,net photosynthetic rate（Pn）,transpiration rate（Tr）,stomatal conductance（Gs） and intercellular CO2 concentration（Ci） of three Musa variety seedling leaves under different drought stress conditions were determined.The results showed that the L value,a value and b value of the three species measured 1d after the drought stress at three stress levels declined in comparison with the control.Compared to the control,the chlorophyll content of ＇Brazil＇ and ＇Diwangjiao＇ under light and moderate stress dropped by 14.9% and 30.4%,29.7% and 45.3% separately,while it increased by 12.8% and 2.3% individually under severe drought stress.The chlorophyll content of ＇Fenjiao＇ was significantly lower than that of the control under three stress levels.There was no simple linear relationship between the leaf color value and chlorophyll content for the three varieties.The Pn,Tr,Gs values of the three varieties significantly declined along with the development of drought stress,while the decrement of Pn value of ＇Brazil＇ was the largest,which decreased by 80.1%,83.4% and 92.4% under the three drought levels.The Ci value of the three varieties was all significantly higher than the control.The results showed that the drought resistance of the three varieties was ordered as ＇Fenjiao＇〉＇Diwangjiao＇〉＇Brazil＇.