采用砂培法,对质量浓度 0(对照)、5、10、15、20 和 30 g· L^-1 NaCl 胁迫条件下长芒草( Stipa bungeana Trin.)、丽色画眉草[Eragrostis spectabilis ( Pursh) Steud.]、狼尾草[Pennisetum alopecuroides ( L.) Spreng.]、‘小兔子’狼尾草(P. alopecuroides ‘ Little Bunny’)、拂子茅( Calamagrostis brachytricha Steud.)、野古草[ Arundinella hirta ( Thunb.)Tanaka]、远东芨芨草[ Achnatherum extremiorientale ( Hara) Keng]、芨芨草[ A. splendens ( Trin.) Nevski] 和须芒草(Andropogon scoparius Michx.)幼苗的存活率和死亡率进行了分析,并根据植株死亡率、植株存活或出现死亡的 NaCl质量浓度和 5 g· L^-1 NaCl 胁迫条件下 6 个生长指标的聚类分析结果对 9 种观赏草的耐盐性进行了评价;在此基础上,对 NaCl 胁迫条件下耐盐性最强的芨芨草生长指标的变化进行了详细分析。 结果表明:采用植株死亡率、植株存活或出现死亡的 NaCl 质量浓度以及生长指标的聚类分析结果都可对供试 9 种观赏草的耐盐性进行评价,评价结果有一定的差异但表现出相似的趋势;综合 3 种方法的评价结果,9 种观赏草的耐盐性可被分为 4 个等级:芨芨草最强;狼尾草、‘小兔子’狼尾草、丽色画眉草和长芒草较强;须芒草中等;拂子茅、远东芨芨草和野古草最弱。 在NaCl 胁迫条件下,芨芨草栽培基质及其渗出液的电导率随 NaCl 质量浓度的提高逐渐增大;而芨芨草的不同生长指标对 NaCl 胁迫的响应有差异,其中,NaCl 胁迫对芨芨草根长的影响较小;随 NaCl 质量浓度的提高,芨芨草的苗高、分蘖数、根数、茎叶干质量和根干质量以及叶绿素相对含量均逐渐降低,而根冠比逐渐增大。 在 NaCl 质量浓度高于 10 g· L^-1条件下,芨芨草幼苗可以存活;而在 NaCl 质量浓度不高于 10 g· L^-1 条件下,芨芨草幼苗可以维持生长。 实验期间的极端高温及极端低温以及栽培基质电导率的变化均对芨芨草幼苗的生长和耐盐性有一定的影响。

 

Survival and death percentages of seedlings of Stipa bungeana Trin., Eragrostis spectabilis (Pursh) Steud., Pennisetum alopecuroides (L.) Spreng., P. alopecuroides ‘Little Bunny’, Calamagrostis brachytricha Steud., Arundinella hirta (Thunb.) Tanaka, Achnatherum extremiorientale (Hara) Keng, A. splendens (Trin.) Nevski and Andropogon scoparius Michx. were analyzed by sand culture method under 0 (control), 5, 10, 15, 20 and 30 g· L^-1 NaCl stress, and their salt tolerances were assessed according to plant death percentage, NaCl concentrations inducing survival or beginning dead of plant and cluster analysis result of six growth indexes under 5 g· L^-1 NaCl stress. On the basis, change of growth indexes of A. splendens with the strongest salt tolerance under NaCl stress was analyzed minutely. The results show that according to plant death percentage, NaCl concentrations inducing survival or beginning dead of plant and cluster analysis result of growth indexes, salt tolerance of the nine grasses tested can be assessed. Although their assessment results are not completely same, but appear similar trend. Combining assessment results based on above three methods, salt tolerance of the nine grasses are classified into four grades: Achnatherum splendens is the strongest; Pennisetum alopecuroides, P.alopecuroides ‘ Little Bunny ‘, Eragrostis spectabilis and Stipa bungeana are stronger; Andropogon scoparius is middle; Calamagrostis brachytricha, Achnatherum extremiorientale and Arundinella hirta are the weakest. Under NaCl stress, electrical conductivity in cultivating substrate and its leachate for A. splendens increases gradually with rising of NaCl concentration. And response of different growth indexes of A. splendens to NaCl stress is vary, in which, effect of NaCl stress on root length is smaller. With rising of NaCl concentration, height, tiller number, root number, dry weight of stem and leaf, dry weight of root and chlorophyll relative content of A. splendens all decrease gradually, while ratio of root-shoot increases gradually. Under NaCl concentration higher than 10 g· L^-1, A. splendens seedling can survive, while maintain growth under NaCl concentration lower than 10 g· L^-1. Extremely high and extremely low temperatures and change of electrical conductivity of cultivating substrate have a certain effect on growth and salt tolerance of A. splendens seedling.