Protective effect of anthocyanin on photosynthetic apparatus of tomato (L. esculentum Mill.) seedling leaves exposed to low temperature and low irradiance

Chino. 探索幼苗叶片花青苷对低温弱光处理的番茄幼苗的光合作用是否具有保护作用。利用硫灯和氙灯下生长的番茄幼苗真叶之间以及野生型(WT)和光敏素双突变体(phyB1phyB2)幼苗真叶之间花青苷含量的差异，以叶绿素荧光为指标，研究花青苷对低温弱光处理的番茄幼苗叶片光合荧光变化的影响。低温弱光(2oC, 100 andmicro;mol photonsand#8226;m-2and#8226;s-1)对番茄幼苗叶片PSⅡ具有显著的抑制作用，但是对PSI活性影响不大。低温弱光处理硫灯和氙灯下的番茄幼苗及硫灯下的WT和突变体番茄幼苗3 h后，硫灯下富含花青苷的番茄 PSⅡ光化学效率Fv/Fm降低到处理前的76.3%，氙灯下的降低到63.3%；能合成花青苷的WT的Fv/Fm降低到处理前的64.3%左右，而不能合成花青苷的phyB1phyB2降低到处理前的53.7%；下降程度显著高于WT。在番茄幼苗叶片不能合成花青苷后，分别生长在硫灯和氙灯下的番茄植株叶片在经过低温弱光处理3 h后，叶片的PSⅡ光化学效率Fv/Fm的变化幅度没有显著的差别；同样，硫灯下WT和phyB1phyB2植株之间也没有显著差别。花青苷对低温弱光逆境处理的番茄叶片的光合机构具有保护作用，这种保护作用极可能与花青素对可见光和紫外光的吸收和屏蔽作用有关。

Inglés. The study looked at tomato seedling development and its susceptibility to low irradiance and low temperature stress. Anthocyanin was tested as a protectant for photosynthetic apparatus exposed to low temperature and low irradiance. Chlorophyll fluorescence was chosen as the probe to assess the extent of photodamage of photosynthesis apparatus. The difference of leaf anthocyanin content between tomato seedlings grown under sulfur lamp and xenon lamp, and the difference between WT and photomorphogenetic mutant phyB1phyB2 were analyzed to study the change of chlorophyll fluorescence in the course of treatment with low temperature and low irradiance. It was found that exposure to low temperature and low irradiance (2℃, 100 μmol photonsand#8226;m-2and#8226;s-1) markedly inhibited PSⅡ activity, but slightly reduced PSI activity. After treatment of 3 h, PSⅡ Fv/Fm in tomato leaves grown under sulfur and xenon lamp decreased to 76.3% and 63.3% of pretreatment, respectively; Similarly, Fv/Fm decreased to 64.3% of pretreatment for anthocyanin-containing WT seedlings and 53.7% for phyB1phyB2 seedlings incapable of anthocyanin accumulation. After tomato plants of L402 and WT grown under sulfur lamp were not able to accumulate anthocyanin, no significant difference was observed in Fv/Fm between plants grown under different light environment or between the two genotypes after treatment of low temperature and low light. Anthocyanin could protect photosynthesis apparatus in the stress environment most likely through absorbing visible and shielding of UV light.