Effects of tuber size and burial depth on germination and plant growth of the submerged macrophyte Vallisneria spinulosa S.Z. Yan at different light intensities
2022
Yuan, Guixiang | Sun, Lijun | Guo, Peiqin | Chen, Zhenglong | Yang, Zhenzhi | Fu, Hui | Jeppesen, Erik
The characteristics of propagules markedly impact the germination and plant growth of submerged macrophytes. Vallisneria spinulosa S.Z. Yan is a common submerged macrophyte and has been widely used in lake restoration projects. The responses of tuber germination and plant growth to different tuber sizes and burial depths are not well known for this species and may vary with light intensity. In this study, the tuber germination and plant growth of V. spinulosa germinated from two levels of tuber sizes (large and small) and two different burial depths in the sediment (5 and 15 cm) were tested at two light intensities (high and low) by measuring morphological and physiological traits. Although light intensity, tuber size and burial depth did not affect the tuber germination, they significantly influenced the morphological and physiological traits of the plants. Light intensity had the greatest effect on plant growth, followed by tuber size, while burial depth had the least effect. High light, large tuber and shallow burial depth favoured the plant growth performance (plant biomass, ramet and leaf numbers). The growth performance of plants germinated from small tubers was more susceptible to changes in light intensity and burial depth. Soluble carbohydrate and free amino acid contents were negatively and starch content positively correlated with the morphological traits. The study highlights the importance of tuber size and burial depth for plant growth as well as their interactions with light, which should be considered when determining lake management and restoration strategies.
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