【专题：红豆属植物多样性保育研究】三种红豆属植物光合特性及叶片显微结构的比较研究

Comparative study on the photosynthetic characteristics and leaf microstructure of three Ormosia Species

关键词:  海南红豆，厚荚红豆，长脐红豆，光合特性，叶片显微结构，叶绿素含量

Key words:  Ormosia pinnata, O. elliptica, O. balansae, photosynthetic characteristics, leaf microstructure, chlorophyll content

摘要:

为探究海南红豆（Ormosia pinnata）、厚荚红豆（O. elliptica）和长脐红豆（O. balansae）共3种红豆属植物的光合特性及其叶片显微结构特征，该研究对3种红豆属植物的光合-光响应曲线、光合-CO2响应曲线、蒸腾速率、气孔导度、叶绿素含量和叶片显微结构等指标进行了测定。结果表明：（1）海南红豆表现出较好的光合能力，其最大净光合速率为5.876 μmol·m-2·s-1，高于厚荚红豆（4.58 μmol·m-2·s-1）和长脐红豆（3.019 μmol·m-2·s-1），表明海南红豆具有更强的碳同化能力和更高的光合效率；（2）海南红豆对CO2的利用更加经济高效，长脐红豆在高CO2浓度下，则具备更大的光合增益潜力；（3）厚荚红豆的Chla、Chlb和Chl(a+b)含量均比海南红豆和长脐红豆高，海南红豆的Chla/Chlb值低于厚荚红豆和长脐红豆，表明厚荚红豆和长脐红豆比海南红豆对光的耐受性更强；（4）海南红豆和厚荚红豆的栅海比（PT/ST）高于长脐红豆；（5）3种红豆属植物叶片的最大净光合速率（Pmax）与表现量子效率（AQY）、叶片上表皮细胞（UET）、下表皮细胞（LET）和栅海比（PT/ST）呈正相关，与类胡萝卜素（Car）含量、叶片海绵组织（ST）、气孔长轴长度（SL）、气孔短轴长度（SW）和单个气孔面积（SA）呈负相关，影响3种红豆属植物叶片的Pmax的关键因子为AQY和PT/ST。综上，在3种红豆属植物引种栽培或生境保护时，应营造适宜的光照环境促进厚荚红豆生长、适当增加CO2浓度有利于长脐红豆生长，而海南红豆凭借良好的光合效益，仍是植被恢复中先锋树种的理想选择。

Abstract:

This study investigated the photosynthetic characteristics and leaf microstructural features of three Ormosia species-Ormosia pinnata, O. elliptica, and O. balansae-by measuring photosynthetic-light response curves, photosynthetic-CO? response curves, transpiration rate, stomatal conductance, chlorophyll content, and leaf microstructure. The results were as follows：(1) O. pinnata exhibited superior photosynthetic capacity, with a maximum net photosynthetic rate (Pmax) of 5.876 μmol·m?2·s?1, which was higher than that of O. elliptica (4.58 μmol·m?2·s?1) and O. balansae (3.019 μmol·m?2·s?1). This suggested that O. pinnata possess a stronger carbon assimilation capacity and higher photosynthetic efficiency. (2) O. pinnata demonstrated greater economic efficiency in CO2 utilization. In contrast, O. balansae exhibited greater potential for photosynthetic gain under high CO2 concentrations. (3) O. elliptica showed higher contents of Chla, Chlb, and total chlorophyll (Chl a+b) compared to O. pinnata and O. balansae. Additionally, the Chla/b in O. pinnata was lower than that in O. elliptica and O. balansae, indicating that the latter two species had a stronger capacity to tolerate high light intensity. (4) The palisade tissue to spongy tissue ratio (PT/ST) of O. pinnata and O. elliptica was higher than that of O. balansae. (5) The Pmax of the three species was positively correlated with the apparent quantum yield (AQY), upper epidermal thickness (UET), lower epidermal thickness (LET), and the PT/ST. Conversely, it was negatively correlated with carotenoid content (Car), spongy tissue thickness (ST), stomatal long axis length (SL), short axis length (SW), and individual stomatal area (SA). The key factors influencing Pmax in the leaves of three species were AQY and PT/ST. In conclusion, when cultivating these three species or conserving their habitats, it is essential to establish an appropriate light environment to promote the growth of O. elliptica and moderately increase CO? concentration to support the development of O. balansae. Meanwhile, O. pinnata, owing to its superior photosynthetic capacity, remains an ideal candidate for pioneer tree species in vegetation restoration initiatives.