Zhang Chun-Ping, Li Yi-Cun, Yuan Feng-Gang, Hu Shi-Jun, Liu Hai-Ying, He Ping
School of Life Sciences, Southwest University, Key Laboratory (Ministry of Education) of Eco-environments of Three Gorges Reservoir Region, Chongqing Key Laboratory of Plant Ecology and Resources Research for Three Gorges Reservoir Region, Chongqing, 400715, PR, China.
Department of Biology and Center for Chinese Medicine Research, Hong Kong University of Science and Technology, Hong Kong SAR, 999077, PR, China.
Bot Stud. 2013 Dec;54(1):18. doi: 10.1186/1999-3110-54-18. Epub 2013 Aug 23.
Soil salinity, one of the major abiotic stresses affecting germination, crop growth, and productivity, is a common adverse environmental factor. The possibility of enhancing the salinity stress tolerance of Cassia obtusifolia L. seeds and seedlings by the exogenous application of 5-aminolevulinic acid (ALA) was investigated.
To improve the salinity tolerance of seeds, ALA was applied in various concentrations (5, 10, 15, and 20 mg/L). To improve the salinity tolerance of seedlings, ALA was applied in various concentrations (10, 25, 50, and 100 mg/L). After 10 mg/L ALA treatment, physiological indices of seed germination (i.e., germination vigor, germination rate, germination index, and vigor index) significantly improved. At 25 mg/L ALA, there was a significant protection against salinity stress compared with non-ALA-treated seedlings. Chlorophyll content, total soluble sugars, free proline, and soluble protein contents were significantly enhanced. Increased thiobarbituric acid reactive species and membrane permeability levels were also inhibited with the ALA treatment. With the treatments of ALA, the levels of chlorophyll fluorescence parameters, i.e., the photochemical efficiency of photosystem II (F/F), photochemical efficiency (F'/F'), PSII actual photochemical efficiency (ΦPSII), and photochemical quench coefficient (qP), all significantly increased. In contrast, the non-photochemical quenching coefficient (NPQ) decreased. ALA treatment also enhanced the activities of superoxide dismutase, peroxidase, and catalase in seedling leaves. The highest salinity tolerance was obtained at 25 mg/L ALA treatment.
The plant growth regulator ALA could be effectively used to protect C. obtusifolia seeds and seedlings from the damaging effects of salinity stress without adversely affecting plant growth.
土壤盐渍化是影响种子萌发、作物生长和生产力的主要非生物胁迫之一，是一种常见的不利环境因素。本研究探讨了外源施加5-氨基乙酰丙酸（ALA）提高决明种子和幼苗耐盐胁迫能力的可能性。
为提高种子的耐盐性，施加了不同浓度（5、10、15和20 mg/L）的ALA。为提高幼苗的耐盐性，施加了不同浓度（10、25、50和100 mg/L）的ALA。10 mg/L ALA处理后，种子萌发的生理指标（即萌发活力、发芽率、发芽指数和活力指数）显著提高。在25 mg/L ALA处理下，与未用ALA处理的幼苗相比，对盐胁迫有显著的保护作用。叶绿素含量、总可溶性糖、游离脯氨酸和可溶性蛋白含量显著增加。丙二醛反应性物质和膜透性水平的增加也被ALA处理所抑制。经ALA处理后，叶绿素荧光参数水平，即光系统II的光化学效率（F/F）、光化学效率（F'/F'）、PSII实际光化学效率（ΦPSII）和光化学猝灭系数（qP）均显著增加。相反，非光化学猝灭系数（NPQ）降低。ALA处理还增强了幼苗叶片中超氧化物歧化酶、过氧化物酶和过氧化氢酶的活性。在25 mg/L ALA处理下获得了最高的耐盐性。
植物生长调节剂ALA可有效保护决明种子和幼苗免受盐胁迫的伤害，且不会对植物生长产生不利影响。
