目的 提高射干Belamacanda chinensis种子及幼苗在盐胁迫条件下的抗逆能力。方法 采用外施亚精胺（ALA）处理，对在盐胁迫下射干种子的萌发及幼苗叶片光合特性各指标进行研究。结果 100 mmol/L NaCl胁迫下射干种子萌发受到严重影响，通过施加ALA（25～100 mg/L）处理，射干种子的各项指标都有所恢复，其中经过75 mg/L ALA处理的效果最为显著，各项指标均达最大值。外源ALA也显著提高了幼苗叶片中叶绿素a、叶绿素b、总叶绿素、类胡萝卜素的量，提高了最大荧光（Fm）、最大光化学效率（Fv/Fm），PSII有效光化学效率（Fv’/Fm’），PSII实际光化学效率（ΦPSII）、光化学淬灭系数（qP），有效降低了非光化学淬灭系数（NPQ）和热耗散速率（HDR），经过ALA处理后光化学反应能量（P）所占的比例显著升高，天线色素热耗散能量（D）和非光化学耗散能量（E）则表现出降低趋势。结论 外源ALA能够提高射干种子的萌发指数，提高幼苗叶片中光合色素量，促进了能量的合理分配，减少激发过剩能量的耗散，提高光合电子传递效率，有效缓解盐胁迫对射干幼苗PSII系统的伤害，提高植株抗胁迫能力。

Objective To increase the resistance of Belamacanda chinensis seeds and seedlings under the salt stress Methods We used 5-aminolevulinic acid (ALA) to treat B. chinensis seeds under salt stress (100 mmol/L NaCl). And several physiological indexes of the seeds were measured, such as the proportion of seed germination and the photosynthetic characters of the seedling. Results The seeds had been damaged heavily by the salt stress (100 mmol/L NaCl)；After being treated by ALA (25—100 mg/L), several physiological indexes of the seeds had been recovered, among which the effect of 75 mg/L ALA treatment was the most significant, and every index reached the maximum. The ALA could increase the contents of chlorophyll a, chlorophyll b, total chlorophyll, and carotenoids significantly, and enhance the maximum fluorescence (Fm), photochemical efficiency of photosystem II (PSII, Fv/Fm), PSII photochemical efficiency (Fv'/Fm'), PSII actual photochemical efficiency (ΦPSII), photochemical quenching coefficient (qP), while decrease the levels of non-photochemical quenching (NPQ) coefficient and heat dissipation rate (HDR) significnatly. The proportion of ALA absorbed light in photochemistry (P) was obviously increased, and the fraction of antenna pigment heat dissipation (D) and excess energy (E) for NPQ indicated downtrend. Conclusion This experiment proved that exogenous ALA could improve the seed germination rate, improve the content of seedlings photosynthetic pigment, promote the reasonable energy distribution, reduce the dissipation of excess excitation energy, improve the efficiency of photosynthetic electron transport, effectively alleviate the damage of seedling, caused by the salt stress, and improve the resistance ability of stress of plant.

国家自然科学基金资助项目（30070080）