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以4个弱光适应性不同的辣椒(Capsicum annuum L.)基因型(甜味型和辣味型)为试材,在人工气候室内研究了弱光(75～100μmol.m-2.s-1)条件下幼苗叶片显微结构、叶绿体超微结构、气孔特征,以及光合特性的适应性变化。结果表明,弱光下辣椒幼苗叶片变薄,栅栏组织/海绵组织比值增加,‘伏地尖’(辣味型)和‘上海圆椒’(甜味型)具有较高的栅栏组织/海绵组织比值;叶绿体数减少,但叶绿体变大,基粒数、基粒厚度和基粒片层增加,淀粉粒增大、增多,2个辣味型材料比2个甜味型材料具有较高的叶绿体数和基粒数。辣椒(甜味型)展叶过程中下表皮气孔密度下降,而展叶14d以后的气孔指数和单片叶气孔数变化不大。弱光下叶片气孔密度、气孔指数和单片叶气孔数减小,但气孔变大,其中‘上海圆椒’气孔纵轴、横轴较正常光照下增加,‘20078’则横轴显著增加;弱光环境中叶片表皮细胞变大并发生扭曲皱褶,气孔与表皮平齐或略显外突,保卫细胞角质层上可观察到明显的环状褶皱。弱光下辣椒幼苗的光饱和CO2同化速率(Asat)、暗呼吸速率(Rd)、夜间呼吸速率(Rn)、光呼吸速率(Rp)、光补偿点(LCP)、光饱和点(LSP)、CO2补偿点(Г)、CO2饱和点(CSP)、羧化效率(CE)以及RuBP最大再生速率下降,表观量子效率(Фi)上升;辣味型较甜味型材料Asat下降幅度较小,并且具有较低的LCP、LSP及其Rd、Rn和Rp。弱光下各基因型辣椒的光合启动时间均有所延长,弱光敏感性材料表现更为明显。
Four low-light-adapted Capsicum annuum L. genotypes (sweet and spicy) were used to study the effects of low light (75-100 μmol.m-2.s- 1) under the conditions of seedling leaves microstructure, chloroplast ultrastructure, stomatal characteristics, and photosynthetic characteristics of adaptive changes. The results showed that the leaves of pepper seedlings became thinner and the ratio of palisade tissue to sponge tissue increased under low light. The ratio of palisade tissue to spongy tissue was higher in ’Vadish spikes’ and ’Shanghai pepper’ (sweet type) ; Chloroplast number decreased, but the chloroplast became larger, the number of basal grains, basal grains and basal lamina increased, starch grains increased and increased. The two spicy materials had higher chloroplast numbers than the two sweet materials And base number. The stomatal density of the lower epidermis in the peppers (sweet type) during leaf unfolding was decreased, while the stomatal index and the number of stomata per leaf after 14 days of leaf unfolding changed little. Under weak light, stomatal density, stomatal index and leaf stomatal number decreased, but the stomata became larger. The vertical axis and lateral axis of ’Shanghai pepper’ increased as compared with normal light, and the horizontal axis of ’20078’ increased significantly. In weak light environment, the epidermal cells became larger and twisted, the stomata and epidermis were flush or slightly protruded, and the obvious circular folds were observed on the stratum corneum. Light Saturated CO2 Assimilation Rate (Asat), Dark Respiration Rate (Rd), Night Respiration Rate (Rn), Light Respiration Rate (Rp), Light Compensation Point (LCP), Light Saturation Point (LSP) The CO2 compensation point (Г), CO2 saturation point (CSP), carboxylation efficiency (CE) and RuBP maximum regeneration rate decreased, and apparent quantum yield (Фi) increased. Asat, And has a lower LCP, LSP and its Rd, Rn and Rp. Under low light, the photosynthetic priming time of all genotypes of pepper were prolonged, and the performance of weak light sensitive materials was more obvious.