Ullah Farhat, Ahmad Mushtaq, Zafar Muhammad, Parveen Bushra, Ashfaq Shomaila, Bahadur Saraj, Safdar Qura-Tul-Ain, Safdar Luqman Bin, Alam Fakhre, Luqman Muhammad
Department of Plant Sciences, Quaid-i-Azam University, Islamabad, Pakistan.
Department of Botany, Rawalpindi Women University, Rawalpindi, Pakistan.
Microsc Res Tech. 2022 Apr;85(4):1410-1420. doi: 10.1002/jemt.24004. Epub 2021 Nov 30.
Pollen micromorphology is not only used to check the functional and structural evolution in plants but also to solve the taxonomic problem related to the classification of plants. Therefore, keeping in view the significance of pollen traits, selected taxa of the subfamily Caesalpiniaceae was collected from different geographical regions of Pakistan. The species were then analyzed under both light microscopy and scanning electron microscopy techniques to investigate the importance of micromorphological characters of pollen in the identification and classification of species. Great variation was recorded in equatorial shape, surface ornamentation, tectum, polar diameter, equatorial diameter, and exine thickness. However, little variation was observed in pollen type, polar shape, and fertility of pollen. The equatorial shape of five types was observed: prolate, prolate-spheroidal, spheroidal-subprolate, subspheroidal-prolate, and subspheroidal. Four types of surface ornamentation, psilate, granulate, clavate, and perforate, were recorded. Tectum of five types, intactate, reticulate regulate, medium reticulate, tactate, and striate, was observed. Sexine was thicker than nexine in all studied species. The largest polar diameter was observed in Caesalpinia pulcherrima 64.1 μm while the smallest in Parkinsonia aculeata 26.1 μm. The largest equatorial diameter was found in C. pulcherrima of 70.25 μm whereas the smallest in P. aculeata 27.57 μm. All the pollens analyzed were tricolporate. All studied species have a fertility ratio of more than 90%. A taxonomic key was developed to show the variation in pollen features and delimit species for the correct identification. In conclusion, the pollen traits were found useful to define species boundaries at various taxonomic ranks and will strengthen the taxonomy of this subfamily. Besides, this study also explored the palynological traits and their implication in the taxonomy of the subfamily Caesalpiniaceae.
花粉微观形态学不仅用于研究植物的功能和结构演化，还用于解决与植物分类相关的分类学问题。因此，鉴于花粉特征的重要性，从巴基斯坦不同地理区域收集了苏木亚科选定的分类群。然后，利用光学显微镜和扫描电子显微镜技术对这些物种进行分析，以研究花粉微观形态特征在物种鉴定和分类中的重要性。在赤道形状、表面纹饰、覆盖层、极轴直径、赤道直径和外壁厚度方面记录到了很大的差异。然而，在花粉类型、极面形状和花粉育性方面观察到的差异较小。观察到五种赤道形状：长球形、长球球形、球-近长球形、近球形-长球形和近球形。记录到四种表面纹饰类型：光滑、颗粒状、棒状和穿孔状。观察到五种覆盖层类型：完整、规则网状、中等网状、触觉状和条纹状。在所有研究的物种中，外壁比内壁厚。在金凤花中观察到最大的极轴直径为64.1μm，而在尖叶决明中最小为26.1μm。在金凤花中发现最大的赤道直径为70.25μm，而在尖叶决明中最小为27.57μm。所有分析的花粉都是三孔沟的。所有研究的物种育性率均超过90%。编制了一个分类检索表，以显示花粉特征的差异并界定物种以便正确鉴定。总之，发现花粉特征有助于在不同分类等级上界定物种界限，并将加强该亚科的分类学。此外，本研究还探讨了苏木亚科的孢粉学特征及其在分类学中的意义。
