滨海盐碱胁迫下白蜡无性系生长及生理特性的响应

为筛选白蜡耐盐速生优良无性系，在滨海盐碱环境胁迫下，以国内收集的42个白蜡种质资源无性系为研究对象，利用相关性和主成分分析法对42个无性系干鲜比、株高、地径以及超氧化物歧化酶(SOD)、细胞膜透性、叶绿素、过氧化物酶(POD) 、丙二醛(MDA)生理代谢等指标进行遗传变异分析和综合评价。结果表明：42个无性系8个指标之间存在一定程度的差异，其中过氧化物酶(POD)变异系数最大，为64.33%，变异幅度25.00~458.30 U/(g·min)；其次为丙二醛(MDA)，变异系数为49.52%，变幅为0.50~7.08 umol/kg；再次为叶绿素和地径，变异系数分别为18.92%和18.56%，变幅分别为1.46~4.26 mg/g和1.15~2.78 cm；相关性分析结果表明，滨海盐碱胁迫下苗木干鲜比、株高和地径与各生理指标之间的相关性均达显著或极显著相关，说明利用生长指标和生理指标对无性系耐盐性进行综合评价，能反映滨海盐碱胁迫后的响应；利用主成分分析法对42份白蜡种质资源无性系综合得分及排名得知，各无性系耐盐碱性由强到弱前10位依次为‘盐3’>‘LC13’>‘济20’>‘R7-2’>‘盐2’>‘环翠3号’>‘胶南11’>‘白蜡4-2’>‘白蜡2’>‘DT21’。因此，初步认为上述10个无性系具有显著速生性和耐盐碱性，可作为盐渍立地造林或抗逆育种的重要应用材料。

Responses of Growth and Physiological Characteristics of Fraxinus Clones to Coastal Saline-Alkaline Stress

In order to screen fine salt-tolerant and fast-growing Fraxinus clones, 42 Fraxinus clones collected in China were studied under coastal saline-alkaline stress. The genetic variation of dry/fresh ratio, plant height, ground diameter, superoxide dismutase (SOD), cell membrane permeability, chlorophyll, peroxidase (POD), malondialdehyde (MDA) physiological metabolism of the 42 clones were analyzed and evaluated by using the correlation and principal component analysis. The results showed that there were some differences among 8 indexes of the 42 clones. The variation coefficient of peroxidase (POD) was the largest (64.33%), and the range of variation was 25.00-458.30 U/(g·min). The variation coefficient of malondialdehyde (MDA) was the second, with a variation coefficient of 49.52% and a variation range of 0.50-7.08 μmol/kg. In terms of chlorophyll and ground diameter, the coefficient of variation was 18.92% and 18.56%, respectively, and the variation range was 1.46-4.26 mg/g and 1.15-2.78 cm, respectively. The results of correlation analysis showed that the dry/fresh ratio, plant height and ground diameter of seedlings under saline-alkaline stress were significantly or extremely and significantly correlated with various physiological indexes, indicating that the comprehensive evaluation of the salt-tolerance of Fraxinus clones by using growth indexes and physiological indexes could better reflect the response of Fraxinus clones to saline-alkaline stress in coastal areas. According to the comprehensive score and ranking of the 42 clones of Fraxinus germplasm resources by principal component analysis, the top 10 clones with saline-alkaline tolerance from strong to weak were ‘Yan 3’> ‘LC13’> ‘Ji 20’ > ‘R7-2’> ‘Yan 2’ > ‘Huancui 3’ > ‘Jiaonan 11’> ‘Baila 4-2’and ‘Baila 2’> ‘DT21’. Therefore, it is preliminarily concluded that the above 10 clones have significantly fast growth and saline-alkaline tolerance, and could be used as important materials for site afforestation or stress tolerance breeding.