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为探寻遮阴对马铃薯光合和荧光特性及吸收光能分配的影响,本研究采用大田试验,以不耐弱光的‘丽薯6号’和耐弱光的‘中薯20’为材料,出苗后用遮光率为70%的黑色遮阳网进行遮阴处理(T),以自然光照为对照(CK),测定了遮阴30 d后马铃薯叶片的光合作用、光响应曲线、CO2响应曲线、光诱导曲线和叶绿素荧光参数的变化。结果表明,遮阴后:(1)净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)、最大净光合速率(Pmax)、光饱和点(LSP)、光补偿点(LCP)较CK显著下降。‘中薯20’的Pn、Pmax、LSP较高,LCP和暗呼吸速率(Rd)较低;(2)不同基因型CO2响应参数无显著差异,但‘中薯20’的、最大羧化速率(Vcmax)和最大电子传递速率(Jmax)较高,CO2补偿点(CCP)较低;(3)高光诱导过程中,‘中薯20’反应较快,光合能力较强;(4)初始荧光(Fo)、最大荧光(Fm)、最大光化学量子效率(Fv/Fm)较CK显著增加,PSⅡ实际光化学量子效率((35)F/Fm′)、表观电子传递速率(ETR)和光化学猝灭系数(q P)较CK显著下降,非光化学猝灭系数(NPQ)呈增加趋势;(5)非光化学热耗散(ФNPQ)和荧光耗散途径(Фf,d)比例显著增加,光化学猝灭耗散途径(ФPSⅡ)比例显著减少,主要以增加热耗散为主。遮阴后,耐弱光基因型‘中薯20’的NPQ和ФNPQ均高于不耐弱光的‘丽薯6号’,说明‘中薯20’的光合机构保护能力更强。综合分析表明,遮阴后耐弱光马铃薯基因型具有较高的净光合速率、较低的光补偿点、较低的CO2补偿点、较快的光诱导反应速度、较高的非光化学热耗散能力。
In order to explore the effects of shading on the photosynthetic and fluorescence characteristics of potato and the distribution of absorbed light energy, field experiments were conducted to investigate the effects of shading on the photosynthetic and fluorescence characteristics of potato and the distribution of absorbed light energy. Shading treatment (T) was carried out on the black shading net with shading rate of 70%, and the photosynthesis, light response curve, CO2 response curve, light response curve, light response curve Induction curve and changes of chlorophyll fluorescence parameters. The results showed that after shading: (1) Pn, Gs, Tr, Pmax, LSP, LCP ) Than CK decreased significantly. (2) There was no significant difference in the CO2 response parameters of different genotypes, but the maximum carboxylation rate of ’Zhongshu 20’ (Vcmax) and maximum electron transfer rate (Jmax), while the CO2 compensation point (CCP) was low. (3) During the high light induction, ’Zhongshu 20’ reacted rapidly and had a strong photosynthetic capacity. (4) The initial fluorescence Fo, Fm, Fv / Fm were significantly higher than those of CK. The actual photochemical quantum efficiency ((35) F / Fm ’), apparent electron transfer rate (ETR) and photochemical quenching (QP) decreased significantly compared with CK and NPQ increased. (5) The ratio of ФNPQ to Фf, d increased significantly, and the photochemical quenching Dissipation dissipation pathway (ФPS Ⅱ) significantly reduced the proportion, mainly to increase the main heat dissipation. After shading, the NPQ and ФNPQ of resistant potato genotype ’Zhongshu 20’ were higher than that of ’Sweet potato 6’, which was not resistant to low light, indicating that ’Zhongshu 20’ had stronger protection ability of photosynthetic apparatus. Comprehensive analysis showed that the shade-tolerant potato genotypes had higher net photosynthetic rate, lower light compensation point, lower CO2 compensation point, faster light-induced reaction rate and higher non-photochemical heat loss Scattered capacity.