Studies On Physiological Response Of Kandelia Obovata For Natural And Artificial Cooling

Kandelia obovata is the northernmost mangrove plant in China,which has important ecological value in the coastal ecosystem.Temperature is an important factor limiting the northward movement of aubergine.This paper took the seedlings of Kandelia obovata from 11provenances as the research object,set up the facility cultivation test and field test,and observed the differences of plant height,ground diameter,biomass,proline,soluble sugar and other indicators in different growth seasons under natural temperature conditions,as well as the semi-lethal temperature of low temperature of leaves.At the same time,set up 0?,4?and 18?three temperature gradient under by the temperature control,the determination of different provenance in seedling leaves MDA content,soluble protein,soluble sugar,SOD activity and proline content change rule.The test results show that:1.The maturation stage of 11 provenance was different,and the maturation stage of hypocotyl was delayed with the increase of latitude.The weight and cotyl roughness of different species were significantly different,and the change was first increased and then decreased with the increase of Kandelia obovata latitude.The biomass of hypocotyl in the middle latitude distribution area of was significantly higher than that in the low and high latitude area.The high growth peak of Kandelia obovata seedlings was from June to August,and the growth peak of ground diameter was from July to September.The biomass of Kandelia obovata in the field?mean 12.78g?was significantly higher than that in the facility cultivation?mean 6.75g?.The biomass of roots,stems and leaves of Yueqing provenance was significantly increased,while that of Haikou and Shenzhen provenance was significantly lower than that of another provenance.The total biomass of Zhanjiang,Beilunhekou,Zhangjiangkou,Quanzhou and Cangnan provinance under field cultivation conditions was not significantly different,indicating that Cangnan had a short growth period and low seedling biomass,but showed strong adaptability in the wild.The net photosynthetic rate,stomatal conductance,intercellular CO₂ concentration and transpiration rate of Kandelia obovata seedlings were high in summer and low in winter.The winter biomass index of facility cultivation was positively correlated with the seeding weight,the middle cotyledon roughness and breeding time,and was positively correlated with the top seed roughness,and negatively correlated with the source latitude.2.Under natural cooling conditions,the seed sources of Fuding,Yueqing and Cangnan had higher SOD activity and proline content,and the soluble sugar content in Beilun and Zhanjiang was higher,respectively,196.05mg/g and 34.26 mg/g,and the soluble sugar content in facility cultivation experiment was about 6 times that in field experiment.3.Kandelia obovata leaf temperature of 11 provenances were lethal temperature at-9.0?^-15.2?,in order from high to low order Cangnan?-15.2??,in Shenzhen?-14.6??,Zhanjiang?-14.4??,Fuding?-14??,Quanzhou?-12.3??,Yueqing?-12.2??,Beilunhekou?-11.5??,Haikou?-10.3??,Shankou?-9.9??,Jiulongjiangkou?-9.0??.4.Artificial low-temperature stress test found that 0?processing,Fuding,Cangnan,Zhanjiang provenance soluble sugar high osmotic regulation substances content is higher than other provenance,the source of the median lethal temperature is low in low temperature.