寡照胁迫对设施葡萄叶片光合特性的影响及评价

Effects and Evaluation of Low Irradiation Stress on Photosynthetic Characteristics of Grapevine Leaves in Greenhouse

以"红提"葡萄(Vitis vinifera L.)为试材,于人工气候箱设置L1(80μmol·m-2·s-1)、L2(200μmol·m-2·s-1)两种辐射水平,分T1、T3、T5、T7、T9(持续胁迫1、3、5、7、9d)5种胁迫天数对试材进行寡照处理,以L0(600μmol·m-2·s-1)为对照(CK),胁迫结束后统一以L0辐射水平进行16d的恢复试验。测定葡萄叶片相对叶绿素含量、光合参数和叶绿素荧光动力参数等指标,利用主成分分析方法筛选所测指标定义胁迫程度指数(Light stress index,LSI),结合恢复生长法划分寡照胁迫等级。结果表明:(1)寡照胁迫使葡萄叶片光合作用受到抑制,随着寡照胁迫程度加深,葡萄叶片的相对叶绿素含量(SPAD)、光饱和点(LSP)、最大光合速率(Pnmax)、表观量子效率(AQE)、气孔导度(Gs)、蒸腾速率(Tr)、光化学淬灭系数(q P)、光合电子传递速率(ETR)均表现为降低的趋势,非光化学淬灭系数(q N)呈上升趋势。L1处理的各指标变化幅度大于L2处理,胁迫9d时,Pnmax降至CK的26.5%,q N增至CK的1.89倍。Fv/Fm随胁迫时间表现为先增大后减小的趋势,L1T5处理达最大为0.79;(2)寡照胁迫后,0~8d为葡萄叶片光合参数快速恢复阶段,恢复至相对稳定状态需要12d左右。短时轻度寡照胁迫对葡萄叶片光合作用无明显抑制,甚至在恢复光照后表现出一定的刺激作用。长时重度寡照胁迫会对葡萄叶片光合系统造成不可逆损伤。(3)综合不同水平胁迫后葡萄叶片光合参数的恢复情况,结合恢复12d时葡萄叶片的LSI值,将设施葡萄寡照灾害分为无灾0级(L1寡照1d,L2寡照1~3d),轻度灾害Ⅰ级(L1寡照2~3d,L2寡照4~7d),中度灾害Ⅱ级(L1寡照4~7d,L2寡照8~9d),重度灾害Ⅲ级(L1寡照7d以上,L2寡照9d以上)4个等级。

To study the effects of low irradiation （LI） on grape （ Vitis vinifera L., cv Hongti ） growth, a controlled experiment was carried out in growth chambers. Three levels of photosynthetic active radiation （PAR） were set for grapes：normal irradiation [L0, 600μmol（photon）·m-2·s-1] and low irradiation [L1, 80μmol（photon）·m-2·s-1; L2, 100μmol（photon）·m-2·s-1].The experiment lasted for 9d, then all groups of grapes were transferred to L0 to recover for 16d. The principal component analysis was used to screen the relative chlorophyll content, photosynthetic parameters, and chlorophyll fluorescence dynamics parameters; light stress index （LSI） was defined, and the stress level was classified combined with recovery growth. The results showed that, （1） the photosynthesis was inhibited by LI, relative chlorophyll content （SPAD）, light saturation point （LSP）, photosynthetic rate at irradiation saturation （Pnmax）, apparent quantum efficiency （AQE）, stomatal conductance （Gs）, transpiration rate （Tr）, photochemical quenching coefficient （qP）, and electron transport rate （ETR） decreased under LI, while the non-photochemical quenching coefficient （qN） was opposite. The change of all indices under L1 was bigger than that of L2, after 9 d, Pnmax decreased to 26.5%, while qN increased to 189%, compared to CK. Maximal photochemical efficiency of PSII （Fv/Fm） increased at first, and then decreased with an increase of stress time, it peaked on the 5th d under L1. （2） The quick recovery stage of photosynthetic parameters was 0-8d, and it took about 12d to resume to CK or a relatively stable state.（3） Taking the recovery state of photosynthetic parameters into consideration, and combining with the LSI at 12d of recovery, the LI disaster level was divided into four grade, that is level 0 （1d under L1, and 1-3d under L2）, levelⅠ （2-3d under L1, and 4-7d under L2）, level Ⅱ （4-7d under L1, and 8-9d under L2）, and level Ⅲ （more than 7d under L1, and more than 9d under L2）.