摘要
以耐海水菠菜品种荷兰3号和海水敏感品种圆叶菠菜为材料,采用水培方法,研究了海水胁迫对菠菜叶片、根系质膜的伤害作用以及叶片光合作用、叶绿素荧光参数的影响.结果表明:(1)海水胁迫对荷兰3号单株干重影响不大,而显著降低圆叶菠菜的单株干重,并使2个品种植株的叶片和根系MDA含量增加,质膜透性增大,叶片光合色素含量降低,但荷兰3号的变化幅度(叶片MDA除外)小于圆叶菠菜.(2)海水胁迫下,短期内2个品种由于气孔限制引起叶片胞间CO2浓度(Ci)降低,净光合速率(Pn)下降;长期胁迫下,荷兰3号Pn恢复到对照水平,而圆叶菠菜同化力下降,Pn降低.(3)海水胁迫对荷兰3号光化学猝灭系数(qP)影响不大,实际光化学效率(ΦPSⅡ)明显升高,而圆叶菠菜的qP和ΦPSⅡ均下降;荷兰3号初始荧光(F0)的下降幅度和非光化学猝灭系数(qN)上升幅度比圆叶菠菜大;2个菠菜品种的最大光化学效率(Fv/Fm)均下降,但荷兰3号光抑制程度(1-qP/qN)的升高幅度比圆叶菠菜小.研究结果说明,海水胁迫下,2个耐性不同的菠菜品种植株都产生了光合作用的光抑制和光氧化伤害,使膜质过氧化和叶绿素含量降低;耐性强的品种能够较多地将光能用于光化学反应,热耗散能力较强,光抑制程度较低,膜系统和光合色素受到活性氧的破坏程度较低,保持了较高的净光合速率,最终可明显降低海水胁迫对植株生长的影响.
The effects of seawater stress on injury of membrane of roots and leaves, photo-pigment, photo-synthesis and chlorophyll fluorescence of two spinach cultivars,‘ Helan No. 3＇ and ‘Yuanye spinach’ were investigated by hydroponics. The results showed that dry mass per plant of cv. ‘ Helan No. 3’ was not obviously affected by seawater,but cv. ‘ Yuanye spinach’ was decreased remarkably. During exposure to stress of seawater,MDA content and membrane permeability were both increased, but photo-pigment of leaves was reduced,and theirs change range of cv.‘ Helan No. 3’ was little than that of cv. ‘Yuanye spinach’ （except MDA content of leaves）. Stomata limitation of two spinach cultivars induced decrease of Ci and Pn in short term on seawater stress. However,in long term on seawater stress,Pn of cv. ‘ Helan No. 3’ resumed to normal level,but Pn of cv. ‘ Yuanye spinach’ continued to decrease as a result of its assimilation decreased. The analyses of chlorohyll fluorescence kinetica parameters shows that there was little effect on qP of cv. ‘ Helan No. 3 ’ but ФPS Ⅱincreased obviously under seawater stress,that of cv. ‘ Yuanye spinach ’declined when exposure to seawater stress. Decrease amplitude and increase range of cv. ‘ Helan No. 3’ were greater than that of cv. ‘Yuanye spinach＇. Fv/Fm of two spinach cultivars were declined ,but the increase of 1-qP/qN of cv. ‘Yuanye spinach＇ was higher than that of cv. ‘ Helan No. 3＇ under seawater stress. These results suggest that two spinach cuhivars were iniured by photo-inhibition and photo-oxidation on seawater stress,that lead lipid to peroxidize and Chl to decompose. However,tolerant cultivar such as cv. ‘Helan No. 3＇ applied more light energy to photochemical reaction, and caloric dissipatior ability was strong,which was depended on xanthophylls cycle. The degree of photo-inhibition was lower ROS, which was excited by excess light energy,were less destroyed membrane system and photopigment to maintain a higher level of Pn. Therefore seawater stress had little effect on growth of tolerant cultivar.
出处
《西北植物学报》
CAS
CSCD
北大核心
2008年第4期737-744,共8页
Acta Botanica Boreali-Occidentalia Sinica
基金
高校博士点科研基金(20050307031)
江苏省自然科学基金(BK2006140)
关键词
海水胁迫
菠菜
光合特性
叶绿素荧光
seawater stress
spinach, photosynthesis
chlorophyll fluorescence
