Effects of light on the seedling growth and photosynthetic physiology of the sympatric invasive lianas Dolichandra unguis-cati and Anredera cordifolia

Abstract

In order to explore the adaptation of sympatric invasive lianas Dolichandra unguis-cati and Anredera cordifolia to light intensity, and to study the effects of different levels of light intensity on their seedling growth and photosynthetic physiology, field shading experiments were conducted. We also selected the sympatric native lianas Hedera nepalensis var. Sinensis as a control. The results showed that, under light shade and strong light, the growth of D. unguis-cati was the best. The growth parameters, net photosynthetic rate, and water use efficiency of D. unguis-cati were the highest, and the contents of photosynthetic pigments were the highest under different light conditions. These results indicated that sufficient light could significantly promote the biomass accumulation and gas exchange of D. unguis-cati, and that D. unguis-cati could maintain efficient light trapping and light protection abilities under different light environments. Under heavy shade, the growth rate of A. cordifolia was the best. The growth parameters of A. cordifolia were significantly greater than those of D. unguis-cati and H. nepalensis var. Sinensis, and the gas exchange parameters were significantly greater than those of H. nepalensis var. Sinensis. However, the growth of the shoot system of A. cordifolia was almost halted under strong light, and the growth indexes were weaker than those of H. nepalensis var. Sinensis. In conclusion, the seedlings of D. unguis-cati had a strong ability to withstand strong light stress, and the seedlings of A. cordifolia had a strong shade tolerance but not strong light stress.