Das Sani, Paul Suman, Kar Priyashi, Mili Marami, Bose Antara, Datta Badal Kumar
Plant Taxonomy and Biodiversity Laboratory, Department of Botany, Tripura University, Suryamaninagar, Tripura, India.
Microsc Res Tech. 2025 Mar 16. doi: 10.1002/jemt.24849.
The Papilionoideae is a taxonomically complex subfamily within the Fabaceae. Pollen characteristics are often used as additional diagnostic features in the taxonomy of Papilionoideae. Unfortunately, the pollen morphology of the Papilionoideae in India remains poorly understood. This study aims to bridge the palynological knowledge gap in the Papilionoideae taxa, focusing on Northeast India. In this investigation, light and scanning electron microscopy (SEM) were employed to examine the pollen morphology of 10 species belonging to nine genera of Papilionoideae: Aeschynomene americana, Cajanus scarabaeoides, Calopogonium mucunoides, Crotalaria calycina, Crotalaria spectabilis, Grona triflora, Lablab purpureus, Pueraria phaseoloides, Tephrosia candida, and Uraria crinita. The pollen grains were prepared using Wodehouse's method; photomicrographs were taken to describe and measure the pollen traits. Pollen traits such as size, aperture number, and shape are stable traits, while exine sculptures, P/E ratio, and gap between two adjacent colpi (GBC) traits can differentiate Papilionoideae taxa. Most of the species (nine species) had tricolporate pollen grains except Aeschynomene americana with syncolporate pollen. Medium-sized pollen was observed in most of the studied species (eight species), except with small-sized pollen grains (A. americana, C. calycina). Three distinct pollen shapes were identified among the studied species: oblate-spheroidal (six species), prolate-spheroidal (three species), and prolate in Uraria crinita. Different types of exine sculpture observed were reticulate, fossulate, fossulate-verrucate, perforate, foveolate-reticulate, foveolate-granulate, rugulate-perforate, and psilate-perforate. The first two principal component analysis (PCA) axis showed 60.3% of the total data variance. Polar axis (PA), equatorial diameter (ED), apocolpium, mesocolpium, and GBC, colpi breadth (ColpiB), P/E, and nexine (> 0.7) contribute significantly to the PCA. Further, a taxonomic key has been prepared based on the pollen morphological characters for correct species identification. This study strengthens and validates the subfamily's taxonomic status and will serve as a foundation for more phylogenetic and molecular research on Papilionoideae.
蝶形花亚科是豆科中一个分类复杂的亚科。花粉特征常被用作蝶形花亚科分类中的附加诊断特征。遗憾的是，印度蝶形花亚科的花粉形态仍知之甚少。本研究旨在填补蝶形花亚科类群在孢粉学知识上的空白，重点关注印度东北部地区。在这项调查中，利用光学显微镜和扫描电子显微镜（SEM）研究了蝶形花亚科9个属的10个物种的花粉形态：美洲合萌、大翼豆、毛蔓豆、萼花猪屎豆、美丽猪屎豆、三裂叶野葛、扁豆、菜豆型葛藤、白花灰叶和长刺狸尾豆。花粉粒采用沃兹沃思方法制备；拍摄显微照片以描述和测量花粉特征。花粉大小、萌发孔数量和形状等特征较为稳定，而外壁纹饰、极轴与赤道轴比值（P/E）以及相邻两条沟之间的间距（GBC）等特征可用于区分蝶形花亚科类群。除美洲合萌为聚沟花粉外，大多数物种（9个物种）具有三沟花粉粒。在大多数研究物种（8个物种）中观察到中等大小的花粉，只有美洲合萌和萼花猪屎豆为小粒花粉。在所研究的物种中鉴定出三种不同的花粉形状：扁球形（6个物种）、长球形（3个物种）以及长刺狸尾豆的长形。观察到的外壁纹饰类型有网状、蜂窝状、蜂窝状 - 瘤状、穿孔状、小窝状 - 网状、小窝状 - 颗粒状、皱波状 - 穿孔状和光滑 - 穿孔状。前两个主成分分析（PCA）轴显示了总数据方差的60.3%。极轴（PA）、赤道直径（ED）、沟间区、沟中区、GBC、沟宽（ColpiB）、P/E以及内层（> 0.7）对主成分分析有显著贡献。此外，还基于花粉形态特征编制了分类检索表，以正确鉴定物种。本研究加强并验证了该亚科的分类地位，将为蝶形花亚科更多的系统发育和分子研究奠定基础。
