草花苗期耐盐性鉴定及综合评价

Identification and Comprehensive Evaluation of Salt Tolerance of Grass Flowers at Seedling Stage

本试验以15种草花为对象,采用NaCl对其幼苗进行盐胁迫处理,以预试验方式研究不同浓度NaCl对草花幼苗鲜重干重、根冠比等生长指标以及叶片抗氧化酶(SOD、POD、CAT)活性、脯氨酸含量等生理指标的影响,并在预试验筛选确定适宜盐胁迫浓度的基础上测定计算该浓度胁迫下各草花的植株形态和生理指标,并对两类指标进行相关性、主成分及聚类分析,对15种草花幼苗的耐盐性进行鉴定评价。结果表明:只有金盏菊的地上部鲜重干重高于对照,其它草花的地上部鲜重干重、地下部鲜重干重均受到不同程度的抑制。耐盐草花金盏菊和向日葵的MDA含量低于对照,盐敏感草花小丽花的MDA含量是对照的3.5倍。耐盐性强的草花(向日葵、金盏菊)其脯氨酸含量增加程度极显著高于盐敏感草花(蜀葵、蒲公英,等)。主成分分析结果显示,相对含水量、根冠比、SOD活性、脯氨酸含量可作为草花幼苗耐盐性的主要鉴定指标。聚类分析结果显示,15种草花苗期的耐盐性可划分为四类:第一类包括小丽花、万寿菊和蜀葵,其耐盐性最弱;第二类包括耧斗菜、假龙头、须苞石竹和百日草,其耐盐性较弱;第三类包括蒲公英、波斯菊、松果菊、半枝莲、常夏石竹和地被菊,其耐盐性较强;第四类包括金盏菊和向日葵,其耐盐性最强。

In this experiment, 15 species of grass flowers were treated with NaCl for salt stress, and the effects of different concentrations of NaCl on growth indexes such as fresh weight, dry weight, root-shoot ratio, and physiological indexes such as antioxidant enzyme(SOD, POD, CAT) activity and proline content in leaves of grass flower seedlings were studied in a pre-test. On the basis of suitable NaCl concentration determined by pre-test, the plant morphology and physiological indexes of each grass flower species under the stress were measured and calculated. The correlation, principal component and cluster analysis of the two kinds of indexes were carried out to identify and evaluate the salt tolerance of 15 species of grass flower seedlings. The results showed that only the above-ground fresh weight and dry weight of Calendula officinalis were higher than those of the control. The above-ground fresh and dry weight and underground fresh and dry weight of other grass flowers were inhibited to varying degrees. The MDA content of salt-tolerant grasses Calendula officinalis and Helianthus annuus were lower than that of the control, while that of salt-sensitive grass Dahlia pinnata was 3.5 times of that of the control. The increase of proline content in salt-tolerant grass flowers(Helianthus annuus, Calendula officinalis) was significantly higher than that in salt-sensitive grass flowers(Alcea rosea, Taraxacum mongolicum, etc.). The results of principal component analysis showed that relative water content, root-shoot ratio, SOD activity and proline content could be used as the main indexes to identify the salt tolerance of grass flower seedlings. The results of cluster analysis showed that the salt tolerance of the 15 grass flowers at seedling stage could be divided into four categories: the first category included Dahlia pinnata, Tagetes erecta and Alcea rosea, which had the weakest salt tolerance. The second group included Aquilegia viridiflora, Physostegia virginiana, Dianthus barbatus and Zinnia elegans, which were less tolerant of salt. The third group included Taraxacum mongolicum, Cosmos bipinnata, Echinacea purpurea, Scutellaria barbata, Dianthus plumarius and Chrysanthemum morifolium, which had stronger salt tolerance. The fourth group including Calendula officinalis and Helianthus annuus had the most salt tolerance.