Warwick Nigel W M, Hailey Luke, Clarke Kerri L, Gasson Peter E
School of Environmental and Rural Science, University of New England, Armidale, New South Wales 2351, Australia.
Jodrell Laboratory, Royal Botanic Gardens, Kew, Richmond, Surrey TW9 3DS, UK.
Ann Bot. 2017 Jun 1;119(8):1249-1266. doi: 10.1093/aob/mcx019.
This study investigates the structural diversity of the secondary xylem of 54 species of Acacia from four taxonomic sections collected across five climate regions along a 1200 km E-W transect from sub-tropical [approx. 1400 mm mean annual precipitation (MAP)] to arid (approx. 240 mm MAP) in New South Wales, Australia. Acacia sensu stricto ( s.s. ) is a critical group for understanding the effect of climate and phylogeny on the functional anatomy of wood.
Wood samples were sectioned in transverse, tangential and radial planes for light microscopy and analysis.
The wood usually has thick-walled vessels and fibres, paratracheal parenchyma and uniseriate and biseriate rays, occasionally up to four cells wide. The greater abundance of gelatinous fibres in arid and semi-arid species may have ecological significance. Prismatic crystals in chambered fibres and axial parenchyma increased in abundance in semi-arid and arid species. Whereas vessel diameter showed only a small decrease from the sub-tropical to the arid region, there was a significant 2-fold increase in vessel frequency and a consequent 3-fold decrease in the vulnerability index.
Although the underlying phylogeny determines the qualitative wood structure, climate has a significant influence on the functional wood anatomy of Acacia s.s. , which is an ideal genus to study the effect of these factors.
本研究调查了从澳大利亚新南威尔士州沿东西向1200公里样带的五个气候区域收集的四个分类组中的54种金合欢属植物次生木质部的结构多样性，样带跨度从亚热带（年平均降水量约1400毫米）到干旱地区（年平均降水量约240毫米）。狭义金合欢属是理解气候和系统发育对木材功能解剖影响的关键类群。
将木材样本切成横向、切向和径向切片，用于光学显微镜观察和分析。
木材通常具有厚壁导管和纤维、傍管薄壁组织以及单列和双列射线，偶尔可达四个细胞宽。干旱和半干旱物种中胶状纤维的丰度较高可能具有生态意义。在半干旱和干旱物种中，分隔纤维和轴向薄壁组织中的棱柱晶体丰度增加。从亚热带到干旱地区，导管直径仅略有减小，而导管频率显著增加了2倍，脆弱性指数相应降低了3倍。
虽然基础系统发育决定了木材的定性结构，但气候对狭义金合欢属的木材功能解剖有显著影响，该属是研究这些因素影响的理想类群。
