不同种源水曲柳耐倒春寒变异分析及种源选择OA

To explore the damage of late spring coldness stress to Fraxinus mandshurica from different provenances and screen out excellent cold-resistant provenances,two-year-old seedlings of 16 Fraxinus mandshurica provenances from Northeast China were used as experimental materials.After investigating differences in bud break phenology,artificial simulation of late spring coldness stress was applied to seedlings at the bud break stage(Level 2-3).Systematic analysis was conducted on freezing injury rate,phenology,growth,and key physiological and biochemical indices after stress,and correlation analysis was carried out in combination with climatic factors.The results showed that:there were highly significant differences in bud break stages among the 16 provenances,following the pattern that provenances from higher latitudes exhibited earlier bud break,while those from lower latitudes showed later bud break.Late spring coldness in the Maoershan Area mostly occurred from early or late May;during this period,seedlings at bud break stage Level 2-3(new buds emerging to leaf expansion)suffered the most severe damage.The Amuer provenance reached bud break stage Level 4 on May 22,with fully expanded leaves,which could effectively avoid the damage of late spring coldness to new buds.After artificial simulation of late spring coldness stress,the freezing injury rate among provenances varied from 16.00%to 75.00%(average:38.10%).The terminal bud set stage and leaf abscission stage were advanced,the growing period was shortened,and the increments of plant height and ground diameter decreased by 12.70%and 7.40%,respectively.Additionally,peroxidase(POD)activity and flavonoid content increased,while photosynthetic pigment and lignin contents decreased significantly.Based on the changes in growth,phenology,and key physiological and biochemical indices,as well as the correlation analysis between each index and climatic factors,three excellent late spring coldness-resistant provenances(Amuer,Dailing,and Nancha)were screened out at a selection intensity of 20%.