外源亚精胺对干旱胁迫下不同品种番茄幼苗光合作用的影响

Effects of exogenous spermidine on photosynthesis of tomato seedlings under drought stress

以耐旱性不同的2个品种番茄(‘毛粉802’和‘皇冠’)为试材,采用营养液栽培,研究了7.5%聚乙二醇(PEG)模拟的干旱胁迫下喷施外源亚精胺(Spd)对番茄幼苗植株光合作用的影响。结果表明,干旱胁迫下,与对照相比,番茄幼苗叶片的净光合速率(Pn),气孔导度(Gs),蒸腾速率(Tr)都显著下降;在胁迫后期,胞间CO2浓度(Ci)显著高于对照。表明在胁迫前期番茄幼苗叶片净光合速率的降低是由气孔限制所造成,而在胁迫后期则是由非气孔限制所造成。喷施0.1 mMSpd能提高干旱胁迫下番茄幼苗叶片的Pn,Gs和Tr,在胁迫后期能减缓Ci的升高,表明在干旱胁迫下,外源Spd能缓解叶片气孔的关闭,促进植株对CO2的吸收,提高植株的光合能力,外源Spd对不耐旱品种‘皇冠’的效果更显著。

Two cultivars were used as test materials and the effect of exogenous spermidine（Spd） on photosynthesis of tomato（Lycopersicon esculentum M.） seedlings under drought stress induced by 7.5% polyethylene glycol（PEG6000） was studied in hydroponics culture.The results showed that drought stress caused a significant decrease in the net photosynthetic rate（Pn）,transpiration rate（Tr）,stomatal conductance（Gs） and intercellular CO2 concentration（Ci） of tomato seedlings.The intracellular CO2 concentration（Ci） was significantly higher than that of the control during the later period of drought stress,which suggested that the decrease in Pn in tomato seedlings＇ leaves mainly resulted from the stomatal limitation during the earlier period of stress,but non-stomatal limitation during the later period.Compared with the drought treatment,exogenous Spd increased Pn,Gs and Tr in the seedling leaves of the two tomato cultivars and decreased Ci during the later period under drought stress.These results indicated that exogenous Spd could improve photosynthesis of tomato seedlings by preventing stoma closure and stimulating CO2 uptake.The mitigative effects of exogenous Spd in drought-sensitive cv.Huangguan were greater than those in high drought-resistant cv.Maofen802.