Responses of physiological and anatomical traits of leaves and fine roots to stumping height of Tilia amurensis

To investigate the effects of different stumping heights on leaf and root functional traits of T. amurensis and provide reference for its plantation cultivation.

Gas exchange parameters, chlorophyll content, anatomical, the content of soluble sugar and starch of leaves and fine roots were determined and analyzed under four treatments: stubble 15 cm (T1), stubble 10 cm (T2), stubble 5 cm (T3), and unleveled stubble (CK).

The number of sprout strips was the highest and the length increased significantly under T3 treatment. Stumping significantly increased the net photosynthetic rate, transpiration rate, stomatal conductance and water utilization of leaves, and the T3 treatment was the most effective, which increased 84.3%, 74.9%, 45.1% and 42.3%, respectively, compared with CK. The daily trend of the net photosynthetic rate and transpiration rate, all treatments had obvious bimodal curves (except for T3), which had a single peak curve, and both peaks appeared at 9: 00 a.m. and 13: 00 p.m. The daily trend of water use efficiency was all bimodal, but the time of the peaks appeared was different. The content of chlorophyll of all treatments increased after stubble. Among them, the chlorophyll a and b of T3 increased the most, which increased by 64.3% and 35.1% compared with CK, respectively. The thickness of palisade tissue and spongy tissue in the leaves increased significantly after stumping. However, the palisade tissue thickness decreased with the decrease of stumping height, among which the increase of T1 treatment was the most significant, increased by 40.1% compared with CK; the sponge tissue thickness increased with the decrease of stumping height, and the increase of T3 treatment was the most significant, increased by 24.4% compared with CK. The upper and lower epidermal thicknesses of the leaves after stumping was significantly lower than that of CK, and increased with decreasing stumping height. T3 treatment decreased by 27.1% and 45.4%, respectively, compared with CK. Compared with CK, the vascular bundle diameter, thickness of cortex, and root diameter of fine roots decreased after stumping. The content of sugar and starch in the leaves in all treatments was lower than that of CK, while in the roots were higher than that of CK.

Stubble had a certain effect on the growth of leaves and fine roots of T. amurensis. When the stumping height is 5 cm, the compensatory growth is the most significant, which is a relatively suitable stumping height.