外源NO对NaCl胁迫下番茄幼苗生长及光合特性的影响

Effect of exogenous nitric oxide on growth and photosynthetic charateristics in tomato seedlings under NaCl stress

采用营养液栽培法,以番茄"白果强丰"为试验材料,研究施用外源NO对Na Cl胁迫下番茄幼苗生长、光合气体交换及叶绿素荧光参数、光能分配的影响。结果表明:外源施用NO缓解了Na Cl胁迫造成的生长抑制、提高了Na Cl胁迫下番茄幼苗根系活力、叶片叶绿素a、b及总叶绿素含量、净光合速率(Pn)、实际光化学效率(ΦPSⅡ)、最大光化学效率(Fv/Fm)、光化学猝灭系数(q P)和光化学猝灭系数(NPQ)及光化学反应的相对份额(P),降低了天线热耗散的相对份额(D)、过剩光能(Ex)及光系统Ⅰ(PSI)与光系统Ⅱ(PSII)之间激发能分配不平衡性(β/α-1),表明外源施用NO通过诱导上调Na Cl胁迫下植株光合色素含量、PSII的光化学反应活性和能力,降低光抑制、有效保护PSII免受过多能量的损伤,维持吸收光能的合理分配,从而缓解了Na Cl胁迫对番茄幼苗生长的抑制和提高了耐盐性。

A hydroponic experiment was conducted to investigate the effects of exogenous nitric oxide（NO） on plant growth,photosynthetic gas exchange, chlorophyll fluorescence parameters and energy distribution in the leaves of tomato（Solanum lycopersicum cv. Baiguoqiangfeng） seedling under Na Cl stress. The results showed that the application of exogenous NO alleviated the inhibition of Na Cl stress on tomato growth and significantly increased root vigor level, the contents of chlorophyll a, chlorophyll b and total chlorophyll, net photosynthetic rate（Pn）, actual photochemical efficiency of PSII（ΦPSII）, the maximum quantum yield of PSII（Fv/Fm）, photochemical quenching coefficient（q P）, non- photochemical quenching coefficient（NPQ） and the relative share of the photochemical reaction（P）, and decreased antenna heat dissipation（D）, excess light energy（Ex） and the imbalance of partitioning of excitation energy between PSⅠ and PSⅡ（β/α- 1） in leaves of tomato seedlings under Na Cl stress. These results suggested that exogenous NO effectively alleviated the inhibition of Na Cl stress on tomato growth and increased the salt resistance of tomato seedlings by inducing the up- regulation of photosynthetic pigment content,photosynthetic capacity and photochemical activity of PSⅡ, and reducing photodamage, protecting PSII from damage caused by excess energy, and maintaining energy distribution of PSⅡ more reasonable.