五种菌草苗期对碱胁迫的生理响应及抗碱性评价

Physiological Responses and Alkaline-Tolerance Evaluation on 5 Species of Juncao under Alkaline Stress during Seedling Stage

为探明莱竹、芦竹、巨菌草、象草、稗草5种菌草对碱胁迫的生理响应及抗碱能力,分别以0、50、100、125、150、200mmol·L-1Na2CO3溶液模拟碱胁迫,测定叶片细胞膜透性,丙二醛(MDA)和可溶性糖(SS)含量,超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性,以及恢复试验后植株死亡率,并利用隶属函数法对以上指标进行综合评价。结果表明,随Na2CO3胁迫浓度的升高,5种菌草的相对电导率、MDA含量呈上升趋势,SS含量,SOD、POD、CAT活性呈先升高后下降的趋势;稗草、莱竹、象草、巨菌草、芦竹的生理指标平均隶属函数值分别为0.36、0.95、0.01、0.14、0.83,半致死Na2CO3胁迫浓度分别为107.0、127.7、68.5、78.5、123.0mmol·L-1;5种菌草的抗碱能力强弱为:莱竹>芦竹>稗草>巨菌草>象草。

In order to verify the physiological responses and alkaline tolerance of 5 species ofjuncao, Echi- nochloa crusgalli, Arundo sp., Pennisetum purpureum, Pennisetum sp. and Arundo donax, the physiological in- dexes ofjuncao leaves under alkaline stress （Na_2CO_3） with different concentrations of 0, 50, 100, 125, 150 and 200 mmol·L^（-1） for 5 d, including contents of malondialdehyde （MDA） and soluble sugar （SS）, activities of su- peroxide dismutase （SOD）, peroxidase （POD） and catalase （CAT）, and membrane permeability, were deter- mined respectively. After recovery test, the mortality rates of the 5 juncao species were determined. The all in- dexes were evaluated by using subordinate functions. The result indicated that when the concentration of Na_2CO_3 was increased, SS content and activities of SOD, POD and CAT of the 5 species ofjuncao were first in- creased and then decreased, and the relative electrical conductivity （REC） and MDA content of the 5 juncao species were increased. The half-lethal concentrations of NaECO3 solution orE. crusgalli, Arundo sp., P. pur- pureum, Pennisetum sp. and A. donax were 107.0, 127.7, 68.5, 78.5 and 123.0 mmol·L^（-1）, respectively. Their av- erage membership function values were 0.36, 0.95, 0.01, 0.14 and 0.83, respectively. The alkaline tolerance of 5 juncao species were Arundo sp.〉A, donax〉E, crusgalh〉Pennisetum sp.〉P, purpureum.