樱桃番茄气孔特征和气体交换参数对干旱胁迫的响应

以樱桃番茄为试材,采用基质培养的方法,使用不同浓度PEG 6000(0、5%、10%、15%)模拟干旱胁迫,研究了樱桃番茄叶片气孔特征、气体交换过程和叶绿素素含量对干旱胁迫的响应,以期为提升樱桃番茄在干旱地区土壤种植效率以及耐干旱品种的选育提供参考依据。结果表明:不同干旱处理对气孔长度、气孔周长、气孔面积、气孔宽度和气孔形状指数均产生显著的影响(P<0.05),除了气孔宽度外,均随着干旱胁迫的加剧而减少。随着干旱胁迫的加剧净光合反应速率(Pn)、蒸腾速率(Tr)、气孔导度(Gs)均呈现明显下降趋势(P<0.05)。但是,樱桃番茄叶片的细胞间CO_2浓度(Ci)随着干旱胁迫的加剧而升高,且与对照存在显著差异(P<0.05)。另外,干旱胁迫导致樱桃番茄叶片的水分利用效率(WUE)呈先减少后增加的趋势,但均小于对照。此外,樱桃番茄叶片的叶绿素含量随着干旱胁迫加剧呈现先上升后下降的趋势。表明干旱胁迫条件下樱桃番茄叶片主要通过调整单个气孔结构(气孔开度大小)及气孔分布特征(气孔密度和空间分布格局)及叶绿素含量来进一步优化气体交换效率。该研究结果不仅有助于深入理解干旱胁迫对樱桃番茄气孔特征、气体交换过程和叶绿素含量之间关系的影响机理,而且还将为提升樱桃番茄在干旱地区土壤种植效率以及耐干旱品种的选育提供参考依据。

Responses of Stomatal Traits and Leaf Gas Exchange of Cherry Tomato to Drought Stress

To examine the responses of stomatal traits and gas exchange of cherry tomato to drought stress,cherry tomato seedlings were grown in growth chambers for 15 days with different PEG 6000 concentrations of nutrition medium including control(CK,0%),mild water stress(5%),moderate water stress(10%),and severe water stress(15%).The results showed that the stomatal length,stomatal width,stomatal perimeter,stomatal area and stomatal shape index of cherry tomato seedlings were substantially affected by drought stress(P<0.05),but their maximum values were lower than control,except stomatal width.The net photosynthetic rate(Pn),the transpiration rates(Tr)and stomatal conductance(Gs)of cherry tomato seedling was gradually decreased with the increase of drought stress,but intercellular CO2concentration(Ci)were increased with increasing of drought stress,and significantly higher than Control(P<0.05).Moreover,leaf water use efficiency(WUE)decreases firstly and then increases with increasing of drought stress.In addition,the chlorophyll content featured a bell-shape curve with the increases of drought stress.These results suggested that cherry tomato might maximize the leaf gas exchange efficiency via changing the aperture size and shape of single stoma,the stomatal distribution(stomatal density and spatial distribution pattern of stomata)under salinity stress and the chlorophyll content.The results might be not only important for understanding the relationships among stomatal traits,leaf gas exchange,and chlorophyll content under drought stress,but also provide data and theoretical support for planting cherry tomato on drought soil and selection drought tolerance cherry tomato cultivars.