Some physiological characteristic of Choerospondias axillaris (Roxb.) Burtt & Hill

Abstract

Choerospondias axillaris (Roxb.) Burtt & Hill is a large commercial woody,
fast growing, wide-distribution tree. The research result of some physiological characteristics of Choerospondias axillaris (Roxb.) Burtt & Hill at different ages showed that: Choerospondias axillaris (Roxb.) Burtt & Hill leaves of young trees to mature trees have a thickness of 177.5μm -292.3μm. The thickness of palisade parenchyma is 67.8μm - 121.9μm. The thickness of spongy parenchyma is 65.2μm - 96.2μm. The palisade parenchyma/spongy parenchyma proportion of regenerated trees, 6 - monthold trees in nursery and 1 - year-old trees in plantation forest is 0.95 - 0.97, while the figure of the later ages are above 1. The number of stomata in the leaf down surface is from 85 to 161 per mm2. The total chlorophyll content of leaves in young period (up to 2 - year-old) is 2.53 - 2.88mg/g of fresh leaves, the proportion of dla/dlb is 2.6 - 2.9. By the age of 4, the total chlorophyll content in the leaves is 2.94 mg/g of fresh leaves and the proportion of dla/dlb is 3.0. From 6 years old onwards, the total chlorophyll content is 3.16 - 3.57 mg/g of fresh leaves and the proportion of dla/dlb is greater than 3 (3 - 3.7). Up to 2 - year-old, Choerospondias axillaris (Roxb.) Burtt & Hill is a neutral shade-resistance plant. 4 years old tree, it expresses light neutrality. From 6 years old onward, it is fully photophilic. Choerospondias axillaris (Roxb.) Burtt & Hill leaves are vulnerable at a temperature of 40oC, the higher of temperature, the more vulnerability of the leaves. At a temperature of 60°C, the leaves in the nursery are 9 0% damaged, while the leaves of the older ages are damaged from 40 to 75%