In order to explore the cold resistance of several willow hybrid strains,six shrub willow new strains(4#,8 #,15 #,16 #,18 #,25 #)with good growth traits in the experimental forest in recent years were tested by cryogenic freezing test and post-freezing growth recovery test to examine the cold resistance of hybrid varieties.With different time as the main treatment,four time gradients were set up at 5 d intervals,and with different strains(varieties)as sub-treatments,the cold resistance test of willow hybrid strain was carried out with Salix integra as the control.The results showed that the order of cold resistance was 18 #＞4 #＞Salix integra＞16 #＞25#＞8 #＞15 #.18 # had outstanding performance and strong cold resistance.When affected by low tempera-ture for a long time,the electrolyte seepage rate of 25 #,8 # and 15 # was higher than 50％,and different degrees of freezing damage appeared.During the period of 15-20 d,the electrolyte permeability of all the tested strains(varieties)in the experiment was above 50％,which would affect the growth and development of willow trees,but it had not yet reached the death time.
维普
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