The Comparison Of Waterlogging Resistance Of Ten Tree Species

The plain area on the lower-middle reaches of the Yangtze River is low and flat,the underground water level is often high,and often has the disaster of flood,so waterlogging-enduring tree species are the basis of protecting bank.In rencent years,the waterlogging-enduring crops,afforestation trees and fruit trees are much studied except for ornamental trees,which are rarely reported.Because the kind of waterlogging-enduring tree and shrub is small,nature landscape is comparatively monotonous.With the development of the living standard of the people,the requirement of the water environment has become increasingly high,so people plays attention to the use of tree and shrub which availed to wetland.In order to choosing and enriching tree species for protecting bank,the waterlogging tolerance was analyzed and compared on ten tree species(Pistacia chinensis, Photinia serrulata,Nyssa sinensis,Carya illinoensis,Zelkova schneideriana,Platanus occidentalis,Fraxinus chinensis,Sapium sebiferum,Taxodium macronatum and Salix integra.'Hakuro Nishiki' ).The results are as follows:1 The geographic distribution of ten tree speciesIn this study the geographic distribution of ten tree speices were investigated by the method of related information.The waterlogging resistance of tree was relavent to different habitats,vertical altitude and the annual precipitation.For example,Fraxinus chinensis and Sapium sebiferum existed in subtropica evergreen broad-leaved forest which is in Jiangsu province,Zhejiang province and Sichuan province.2 Changes of morphological characteristics of ten tree species under waterlogging stressThe effects of waterlogging stress on morphological characteristics were investigated in 10 tree species(Pistacia chinensis,Photinia serrulata,Nyssa Sinensis,Carya illinoensis, Zelkova schneideriana,Platanus occidentalis,Fraxinus chinensis,Sapium sebiferum, Taxodium macronatum and Salix integra.'Hakuro Nishiki' ).The results showed that under waterlogging stress,for Pistacia chinensis,Photinia serrulata,Nyssa sinensis,Carya illinoensis,Zelkova schneideriana and Platanus occidentalis,the time for waterlogging index to reach 0.90 was 10,20,25,35,40 and 50 days respectively;the indexes of Sapium sebiferum and Fraxinus chinensis were 0.45 and 0.80 after 50 days;Taxodium macronatum and Salix integra 'Hakuro Nishiki' had no obvious change in 60 days.It was concluded that the adventitious rooting and aerenchyma development of trees are an adaptive mechanism to waterlogging stess,so Fraxinus chinensis,Sapium sebiferum,Taxodium macronatum and Salix integra' Hakuro Nishiki' may be the alternative trees which can green river banks.3 Changes of Physiological and biochemistry characteristics of ten tree species under waterlogging stressUsing proline content,MDA content and electric conductivity as physiological indexes,the waterlogging tolerance of 10 tree species were compared under waterlogging stress.The results showed that electric conductivity and MDA content of different tree species had the trend of increment,but the change of proline content was varied under waterlogging stress.Pistacia chinensis and Photinia serrulata had weak waterlogging resistance with the tolerating waterlogging duration for 5-10d;Nyssa sinensis,Carya illinoensis,Zelkova schneideriana and Platanus occidentalis showed considerable waterlogging resistance with the tolerating waterlogging duration for 25d;Fraxinus chinensis and Sapium sebiferum had stronger tolerance to waterlogging over 45d;while Taxodium macronatum and Salix integra 'Hakuro Nishiki' had the strongest tolerance,no injury sympotom had been appeared in 60d.