Tufail Aasma, Ahmad Farooq, Hameed Mansoor, Ahsan Muhammad, Okla Mohammad K, Siddiqua Umme Habibah, Khalid Noreen, Rashid Madiha, Shah Anis Ali, Hegab Momtaz M, AbdElgawad Hamada
Department of Botany, Division of Science and Technology, University of Education, Lahore, Pakistan.
Department of Botany, University of Agriculture, Faisalabad, Pakistan.
Front Plant Sci. 2023 Jan 19;13:1084706. doi: 10.3389/fpls.2022.1084706. eCollection 2022.
It is well known that different ecotypes adopt different mechanisms to survive under environmental stress conditions. In this regard, each ecotype showed different type of modifications for their existence in a specific habitat that reflects to their ecological success.
Here, differently adapted ecotypes of Bermuda grass [Cynodon dactylon (L.) Pers.] were collected to evaluate their differential structural and functional modifications that are specific to cope with environmental stress conditions. The soil that adheres ecotypes roots were highly saline in case of DF-SD (Derawar Fort-Saline Desert), UL-HS (Ucchali Lake-Hyper Saline) and G-SSA (Gatwala-Saline Semiarid) ecotypes. Soils of S- HS (Sahianwala-Hyper Saline), S-SW (Sahianwala-Saline Wetland) and PA-RF (Pakka Anna-Reclaimed Field) were basic (pH 9 to 10). Soils of UL-HS and PA- HS (Pakka Anna-Hyper Saline), KKL-S (Kalar Kahar Lake-Saline), BG-NS (Botanic Garden-Non Saline) and G-SSA were rich in organic matter, and soil of BG-NS and DF-SD were rich in minerals. Anatomical modifications were performed by using the free hand sectioning technique and light microscopy.
DF-SD is one of the best ecotypes which showed anatomical modifications to cope with environmental changes. These modifications included stem cross-sectional area and leaf sheath thickness that contribute towards water storage, vascular tissues for proficient translocation of solutes and trichomes that provide resistance to water loss. On the other hand, sclerification in root is the only notable modification in the Gatwala Saline Semiarid (G-SSA) ecotype from saline arid habitat where rainfall is not as low as in the Cholistan Desert. Two ecotypes from hyper-saline wetlands, UL-HS and KL-HS showed increased number and size of vascular tissue, central cavity and sclerification in stem which are important for solutes conduction, water loss and salts bulk movement, respectively. The ecotype from reclaimed site was not much different from its counterpart from hyper-saline dryland. Overall, anatomical modifications to maintain water conservation are key mechanisms that have been identified as mediating stress tolerance in C. dactylon ecotypes.
众所周知，不同的生态型在环境胁迫条件下会采用不同的生存机制。在这方面，每种生态型在特定栖息地的生存都表现出不同类型的适应性变化，这反映了它们在生态上的成功。
在此，收集了适应性不同的狗牙根[Cynodon dactylon (L.) Pers.]生态型，以评估它们为应对环境胁迫条件而特有的结构和功能差异变化。对于DF-SD（德拉瓦尔堡-盐碱沙漠）、UL-HS（乌查利湖-高盐碱）和G-SSA（加特瓦拉-盐碱半干旱）生态型，附着其根系的土壤盐分很高。S-HS（萨希安瓦拉-高盐碱）、S-SW（萨希安瓦拉-盐碱湿地）和PA-RF（帕卡·安娜-开垦地）的土壤呈碱性（pH值为9至10）。UL-HS和PA-HS（帕卡·安娜-高盐碱）、KKL-S（卡拉尔卡哈尔湖-盐碱）、BG-NS（植物园-非盐碱）和G-SSA的土壤富含有机质，BG-NS和DF-SD的土壤富含矿物质。采用徒手切片技术和光学显微镜进行解剖学变化研究。
DF-SD是表现出解剖学变化以应对环境变化的最佳生态型之一。这些变化包括有助于储水的茎横截面积和叶鞘厚度、用于高效溶质转运的维管组织以及有助于防止水分流失的毛状体。另一方面，在加特瓦拉盐碱半干旱（G-SSA）生态型中，根系硬化是唯一显著的变化，该生态型来自盐碱干旱栖息地，其降雨量不像乔利斯坦沙漠那么少。来自高盐碱湿地的两种生态型，UL-HS和KL-HS，其茎中的维管组织数量和大小增加、中央腔增大以及出现硬化，这些分别对溶质传导、水分流失和盐分大量移动很重要。来自开垦地的生态型与其来自高盐碱旱地的对应生态型差异不大。总体而言，维持水分保持的解剖学变化是已被确定为介导狗牙根生态型胁迫耐受性的关键机制。
