Wood Anatomical Structure of Rhododendron arboreum Sm. in a Drought Manipulated Experiment under two Forest Types in Western Bhutan Himalayas


Dorji Dukpa1, Om Katel2, and Yeshey Khandu2






Formation of woody structure in plant is a dynamic process and is affected by environmental conditions such as moisture availability. This experiment set up tested the hypothesis that drought leads to changes in wood anatomical characteristics, accompanied by decreased vessel size that is compensated by increased vessel density in Rhododendron arboreum Sm. The study was carried out in a cool temperate broadleaved forest dominated by oak species (Quercus lanata Sm., Quercus griffithii Hook. f. and Thomson ex Miq. and in a cool temperate conifer forest dominated by hemlock – Tsuga dumosa (D. Don) Eichler. R. arboreum wood samples were collected from four homogeneous replicated plots of 725 m2 (two  control and two roofed plots) established in 2014 at each forest type. The wood samples were sliced to 20 µm thickness using microtome, dehydrated using different concentration of ethanol before embedding them onto a glass slide. Micro section image was captured using digital camera and analysed using the software ImageJ32. Drought did not impact wood anatomical characteristics and did not lead to a decrease in vessel size. However, drought led to increased vessel density in both the forest types. At the same time, potential seepage of lateral interflow and leakage from roof may have impacted results and therefore further investigations applying deeper trenching against interflow and good roofing over an extended period are recommended to confirm this present finding.


Keywords: Control plot, roofed plot, vessel density, vessel size, wood structure


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