Department of Plant Sciences, Quaid-i-Azam University, Islamabad, Pakistan.
Department of Biochemistry, Hazara University, Mansehra, Pakistan.
Biomed Res Int. 2022 Jul 25;2022:8225494. doi: 10.1155/2022/8225494. eCollection 2022.
Invasive alien species (IAS) are considered as the second major threat to biodiversity after habitat destruction worldwide. They are aggressive competitors and dominate an ecosystem where they introduce and cause reduction in indigenous diversity. Invasive plants alter the evolutionary pathways of native species by competition, niche displacement, hybridization, introgression, predation, and ultimately extinction of native species. Biological invasion also results in economic and environmental damage and harm to human health. Invasive plants have an effective reproductive as well as dispersal mechanisms. Most invasive plants produce abundant fruits and seeds that are widely disseminated and remain viable in the soil for several years. Invasive plants may change their seed character in order to adapt themselves to the new environment and facilitate their performance. A study on seed coat sculpturing in invasive alien plants collected from Lesser Himalaya region, Pakistan, was conducted using scanning electron microscope to determine the importance of seed morphological characters as an additional tool for identification. Quantitative characters such as seed length and width, macromorphological characters including color, hilum position, and seed shape, and micromorphological characters of seed including surface patterns and periclinal and anticlinal wall of seeds were studied. Findings at the present indicate that most of the seeds were found spherical followed by ovate and elliptical in shape with smooth surface and showed terminal hilum. Almost reticulate seed patterns were observed in seeds. Majority of seeds showed raised anticlinal walls with protuberance periclinal walls. The seeds of were observed with maximum length of 13 mm and with width of 8 mm. Length by width ratio of seeds was also calculated; it was found that maximum L/W ratio was observed in L., i.e., 2.66. Seed characters, both macro- and micromorphological, furnish useful data for classification and delimitation of invasive taxa. This study will help to understand the invasion mechanism in plants due to variations in seed surface, shape, and other characters. Adaptive behavior of the seed during the invasion process of the new ecosystem is also elaborated.
入侵的外来物种（IAS）被认为是仅次于全球栖息地破坏的生物多样性的第二大威胁。它们是具有侵略性的竞争者，在引入并导致本地多样性减少的生态系统中占据主导地位。入侵植物通过竞争、生态位取代、杂交、基因渗入、捕食等方式改变本地物种的进化途径，最终导致本地物种灭绝。生物入侵还会造成经济和环境破坏，并危害人类健康。入侵植物具有有效的繁殖和扩散机制。大多数入侵植物会产生大量的果实和种子，这些果实和种子广泛传播，并在土壤中保持活力数年。为了适应新环境并促进自身的表现，入侵植物可能会改变种子的特性。对从巴基斯坦小喜马拉雅地区采集的入侵外来植物种子的种皮结构进行了研究，使用扫描电子显微镜来确定种子形态特征作为鉴定的附加工具的重要性。研究了种子的定量特征，如种子的长度和宽度，宏观特征，包括颜色、种脐位置和种子形状，以及种子的微观特征，包括表面图案和种皮的垂周壁和切向壁。目前的研究结果表明，大多数种子呈球形，其次是卵形和椭圆形，表面光滑，呈顶端种脐。在种子中观察到几乎是网状的种子图案。大多数种子显示出凸起的垂周壁和突起的切向壁。观察到的种子最长为 13 毫米，最宽为 8 毫米。还计算了种子的长宽比；发现种子的最大 L/W 比出现在 L.中，即 2.66。种子的宏观和微观特征为分类和入侵分类群的划界提供了有用的数据。这项研究将有助于了解由于种子表面、形状和其他特征的变化而导致的植物入侵机制。还阐述了种子在新生态系统入侵过程中的适应行为。
