低温胁迫下不同品种榴莲幼苗叶片解剖结构及光合特性分析OA

To explore the response mechanisms of different durian cultivars under low-temperature stress,compare their cold tolerance,and provide a reference for the breeding,conservation and cultivation of cold-tolerant durian cultivars,seedlings of four main cultivars in Hainan,namely,Kan Yao,Musang King,Monthong,and Black Thorn,were subjected to 10℃ low-temperature stress for 3 days,with 25℃ as the control.The thickness of leaves,upper epidermis,lower epidermis,palisade tissue and spongy tissue was determined,along with chlorophyll a and chlorophyll b contents,net photosynthetic rate(Pn),transpiration rate(Tr),stomatal conductance(Gs)and intercellular CO2 concentration(Ci).Differences in leaf anatomical structure and photosynthetic characteristics among cultivars were compared,and cold tolerance of different cultivars was com-prehensively evaluated by principal component analysis(PCA)combined with membership function method.The results indica-ted that there were significant differences in leaf anatomical structures among the four durian cultivars after low-temperature stress.The palisade/spongy tissue ratio of Kan Yao and Musang King was significantly higher than that of Monthong and Black Thorn.Under control conditions,Kan Yao displayed the highest tissue compactness,which was significantly higher than that of Monthong.After low-temperature stress,significant differences in chlorophyll contents were observed among cultivars.Compared with the control,the net photosynthetic rate,transpiration rate,and stomatal conductance of all four cultivars de-creased,while the intercellular CO2 concentration increased.Comprehensive evaluation indicated that the cold tolerance of the four durian cultivar seedlings under 10℃ low-temperature stress ranked from high to low as follows:Kan Yao＞Musang King＞Black Thorn＞Monthong.