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作者	单位
孙传蛟，谭清文，刘晓雪，张紫刚，孙建云	(1.南京农业大学农学院，农业农村部作物生理生态与生产管理重点实验室，江苏南京 210095 2.南京农业大学生科院，江苏南京 210095)

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中文摘要:

为明确褪黑素对铬（Cr⁶⁺）胁迫下小麦幼苗光合和养分吸收的调节作用，在水培条件下以豫麦51（铬敏感型）和扬麦16（耐铬型）为材料，分析了Cr⁶⁺胁迫下外源褪黑素预处理（100 μmmol·L_-1）后小麦幼苗光合和荧光参数及养分含量的变化。结果表明，Cr⁶⁺胁迫显著降低了小麦叶片叶绿素含量、气孔导度（G_s）和光系统 Ⅱ（PS Ⅱ）活性，导致光合速率（P_n）显著降低；Cr⁶⁺胁迫也显著减弱了根系对营养元素（N、P、K、Mg、Fe和Mn）的吸收和转运。外源褪黑素处理显著提高了Cr⁶⁺胁迫下小麦幼苗的P_n、G_s、叶绿素（a和b）含量、实际光化学效率（Φ_PSⅡ）、最大光化学效率（F_v/F_m）、光化学淬灭（qL）和电子传递能力（ETR），增加了根系和叶片营养元素的含量。综合来看，外源褪黑素会促进Cr⁶⁺胁迫下小麦幼苗对养分的吸收与转运、气孔开放、CO₂传导、光能吸收和电子传递，从而缓解Cr⁶⁺对于小麦幼苗光合的抑制作用。

英文摘要:

To explore the beneficial effect of melatonin on photosynthesis of wheat seedlings under Cr⁶⁺ stress, Yumai 51(Cr-sensitive) and Yangmai 16(Cr-resistant) were used as the experimental materials in this study. The effects of exogenous melatonin pretreatment(100 μmmol·L_-1 melatonin) on the changes of photosynthetic characteristics and nutrient absorption of wheat seedlings under Cr⁶⁺ stress were studied through hydroponic method. The results showed that Cr⁶⁺ stress significantly reduced chlorophyll content, stomatal conductance(G_s) photosystem Ⅱ activity, ultimately resulting significant reduction of net photosynthetic rate(P_n). Besides, Cr⁶⁺ stress significantly reduced the uptake and transport of nutrient elements(N, P, K, Mg, Fe, and Mn) in roots. However, exogenous melatonin pretreatment significantly increased the P_n, G_s, chlorophyll content, actual photochemical efficiency(Φ_PSⅡ), maximum photochemical efficiency(F_v/F_m), photochemical quenching(qL), electron transport rate(ETR), and nutrient element contents in roots and leaves of wheat seedlings under Cr⁶⁺ stress. Therefore, exogenous melatonin pretreatment can improve the nutrient absorption and transport capacity, stomatal opening and CO₂ conduction capacity, light energy absorption and electron transport capacity of wheat seedlings under Cr⁶⁺ stress, and thus alleviate the inhibition of photosynthesis of wheat seedlings under Cr⁶⁺ stress.

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