Growth And Resource Distribution In Heterogeneous Habitats In An Invasive Species Sagittaria Graminea

Most invasive plants experienced inconsistent environment during their invasion, spread and establishment, and it is crucial to understand the factors which control the success of invasive species. Until now, few studies have evaluated the Growth and Resource Distribution in Heterogeneous Habitats in an Invasive species Sagittaria graminea Michx. This study reports the effects of soil substrate, water level grade, salt concentration grade, morphological traits and biomass allocation performance of Sagittaria graminea.Control experiments were carried out to examine the effects of soil substrate, water level grade, salt concentration grade on Sagittaria graminea. Ramets of approximately identical size from a population of a single genotype were planted separately in plastic pots and then grew under different treatments. The results are mainly as follow:1. Under different soil substrate, with the decline of the content of soil substrate, Morphological characters and biomass accumulation tend to decrease, showing that Sagittaria graminea can change their phenotypes to adapt to the lack of nutrient supply. By reducing the root biomass allocation and absorbing nutrients from the soil to increase the biomass allocation in leaves and improve the photosynthesis capacity.2. Under the condition of different water level gradients, different water levels showed significant difference effect on growth state. When completely submerged, the Sagittaria graminea growth was severely inhibited, with a loss of function of sexual reproduction. asexual reproduction takes place to maintain genetic. The growth state of 1/3 and1/2 water level grade is better than that of low water level grade and Completely submerged treatment. This illustrates that the plant has a certain requirement in water level grade to keep normal growth. With the rise of water level, the plant needs to increase root, stem and leaf biomass allocation to guarantee stable growth and a certain height to avoid water suppression. The difference between asexual reproduction and sexual reproduction is negligible, which shows that a certain level of water condition is enough to maintain reproduction allocation stability.3. Under different salinity, different treatments show significant difference in growth state. The plant cannot live under the salt solution of 3.2% concentration and its growth will experience inhibition under 1.6% salt solution condition together with the loss of sexual function. The plant tends to raise the root, stem and leaf biomass allocation to resist the inhibitory effects of salinity, enhance the capacity to ensure asexual reproduction.