Devi Pinki, DeVetter Lisa, Kraft Michael, Shrestha Srijana, Miles Carol
Department of Horticulture, Northwestern Washington Research and Extension Center, Washington State University, Mount Vernon, WA, United States.
Scientific Technical Services, Western Washington University, Bellingham, WA, United States.
Front Plant Sci. 2022 Apr 15;13:878289. doi: 10.3389/fpls.2022.878289. eCollection 2022.
Grafting has become a common practice for watermelon [ (Thunb.) Matsum & Nakai] production in many parts of the world, due to its efficacy against biotic and abiotic stressors. However, grafting success for watermelon is challenging in part due to the complex anatomy of the cucurbit vascular system. The survival of grafted transplants depends on compatibility between the scion and rootstock, which in turn depends on anatomical, physiological, and genetic variables. A better understanding of cucurbit anatomy and graft union formation would inform grafting approaches and transplant management. An anatomical study was conducted by scanning electron microscopy (SEM) at 11 and 25 days after grafting (DAG) with seedless watermelon cultivar 'Secretariat' grafted onto compatible rootstock cultivars 'Pelop' () and 'Tetsukabuto' ( × ) in comparison to non-grafted watermelon and rootstock seedlings. At 11 DAG, the parenchymatic cells of the central pith of grafted plants were dead and a necrotic layer was observed, representing the beginning of callus formation. New xylem strands were formed in the vascular system, connecting the rootstock with the scion. At 25 DAG, fully developed vascular bundles at the graft interface were observed with both scion-rootstock combinations. Although more studies are necessary to characterize the sequence of physiological events after grafting in Cucurbit species, this is one of the first studies to describe the complex anatomical changes that occur during watermelon graft healing.
由于嫁接对生物和非生物胁迫具有抗性，在世界许多地区，嫁接已成为西瓜[（Thunb.）Matsum & Nakai]生产中的常见做法。然而，西瓜嫁接成功具有挑战性，部分原因是葫芦科植物维管系统的解剖结构复杂。嫁接苗的存活取决于接穗和砧木之间的兼容性，而这又取决于解剖学、生理学和遗传学变量。更好地了解葫芦科植物的解剖结构和嫁接愈合形成情况，将为嫁接方法和移植管理提供依据。采用扫描电子显微镜（SEM）对无籽西瓜品种‘秘书’嫁接到兼容砧木品种‘佩洛普’（）和‘铁西瓜’（×）上的嫁接苗在嫁接后11天和25天进行解剖学研究，并与未嫁接的西瓜和砧木幼苗进行比较。在嫁接后11天，嫁接植株中央髓部的薄壁细胞死亡，观察到坏死层，这代表愈伤组织形成的开始。维管系统中形成了新的木质部束脉，将砧木与接穗连接起来。在嫁接后25天，两种接穗-砧木组合在嫁接界面处均观察到发育完全的维管束。尽管需要更多研究来描述葫芦科植物嫁接后生理事件的顺序，但这是首批描述西瓜嫁接愈合过程中发生的复杂解剖学变化的研究之一。
