枝領
枝領（環枝組織，英文：branch collar）是樹主幹與枝條間類似肩膀的位子。枝領形状來自兩種交替生長模式疊加而成，春天是枝條向下生長，夏季則換成主幹的生長包覆其外，最終在枝條基部形成膨大的結構[1]。枝領被視為是枝條穩固的基礎，其旋轉與內部特徵使枝條能夠應付來自各方的壓力[2] 。生理上，枝領也同時影響養分運輸與生長模式 [3] [4]。枝領提供了生物性屏障，避免入侵與腐朽。同時可以有效的診阻擋微生物 [1][5]。合適的修剪技術應保護枝領，以免造成腐朽或疾病等損傷樹木[1]。
定義
在樹藝學中，在主幹和枝條間"肩"形的過度結構稱為枝領或環枝組織 [6]。結構定義為從枝條基部起算，環形膨大的組織[7]。枝領或幹領皆統稱為枝領[6]。
形態學
隨時間推移，主幹擴張的形成層會漸漸覆蓋新長出來的枝條組織，造成主幹結構含住越來越多的枝條[1]。枝條的頂部形成"袋"狀的結構，稱為樹襠(crotch)，其造成主幹與枝條的細胞相互擠壓[1]。枝領組織上形成的窄小通道和閉環都是大量賀爾蒙信號留下的路徑[8]。
参考
- ^ 1.0 1.1 1.2 1.3 1.4 Shigo, Alex. How tree branches are attached to trunks. Canadian Journal of Botany. 1985,. 63(8), 1391-1401 (8): 1391–1401. doi:10.1139/b85-193.
- ^ Müller, Ulrich; Gindl, Wolfgang; Jeronimidis, George. Biomechanics of a branch – stem junction in softwood. Trees. 2006-09-01, 20 (5): 643–648. ISSN 1432-2285. doi:10.1007/s00468-006-0079-x （英语）.
- ^ Eisner, N. J.; Gilman, E. F.; Grabosky, J. C. Branch morphology impacts compartmentalization of pruning wounds. Journal of Arboriculture. 2002 [2022-03-09]. ISSN 0278-5226. （原始内容存档于2021-05-04） （英语）.
- ^ Gardiner, Barry; Quine, Christopher. The mechanical adaption of tree to environmental influences. Proceedings of 3rd Plant Biomechanics Conference: 71–82.
- ^ Nakanishi, Yoshihiro; Takesaki, Ken; Miyaji, Katsuhiko; Kitazawa, Hiroaki. Detection of Candidatus Liberibacter asiaticus from branch collars of citrus trees. Journal of General Plant Pathology. 2016-09-01, 82 (5): 248–253. ISSN 1610-739X. doi:10.1007/s10327-016-0666-7 （英语）.
- ^ 6.0 6.1 Shigo, Alex. How tree branches are attached to trunks. Canadian Journal of Botany. 1985,. 63(8), 1391-1401 (8): 1391–1401. doi:10.1139/b85-193.
- ^ TREES, ASSOCIATES and SHIGO. 2002. [DVD] Directed by A. Shigo. Durham, New Hampshire: Shigo and Trees, Associates.
- ^ Lev-Yadun, Simcha; Aloni, Roni. Vascular differentiation in branch junctions of trees: circular patterns and functional significance. Trees. June 1990, 4 (1). ISSN 0931-1890. doi:10.1007/BF00226240 （英语）.