Response Of Sprouting And Growth To Environmental Factors In Bolboschoenus Planiculmis

Due to the effects of global change and human activities,the wetland ecosystem is undergoing great changes.The frequent occurrence of heavy rainfall events,extreme temperature and a large number of farmland water withdrawal have led to great challenges for wetland plants.To explore the wetland plants under different temperature,the change of hydrological conditions and nutrient factors,this study analyzes the sprouting of tubers on environment and seedling stage of flooding the response of the length and the function of nitrogen added traits,from the perspective of species discusses the sprouting to grow in the shoot,early plant recruitment stages and characteristic of the stage.The effects of flooding depth and temperature on tubers and the effects of flooding duration and nitrogen addition concentration on the growth of B.planiculmis were studied.In order to provide important reference value for species distribution and dispersal direction under the condition of global climate change,the ecological adaptation strategy of B.planiculmis to environmental factors in Songnen Plain was proposed.The results are as follows:(1)Temperature had significant effects on final sprouting percentage(FSP),sprouting rate(SR),survival rate(SRS),relative growth rate(RGR)and mean sprouting time(MST).Specifically,the final tillering rate increased first and then decreased with the increase of temperature in a parabolic relationship,and the basic sprouting temperature was estimated to be 6.2 ?.The mean sprouting time decreased gradually with the increase of temperature.The cumulative sprouting percentage fraction had the longest sprouting time(23 days)at 8 ?,and the shortest sprouting day(4 days)at 28 ?.The height of ramets increased with the increase of temperature,and the survival rate of shoots increased first and then decreased with the increase of temperature,and reached the maximum survival rate of 100% at 22.9 ?.The relative growth rate increased with increasing temperature.The optimum temperature for tuber sprouting and early growth is ranging from 25 °C to 28 °C.(2)Flooding depth had significant effects on final sprouting percentage(FSP),sprouting rate(SR),survival rate(SRS),relative growth rate(RGR)and mean sprouting time(MST).With the increase of the depth of flooding,the final sprouting percentage of B.planiculmis increased firstly and then decreased,and reached the maximum of 96.04%at the depth of 3.92 cm.The average budding time increased with the increase of the flooding depth.According to the cumulative sprouting percentage,the longest sprouting time was 17 days at the depth of 40 cm,and the shortest germination time was 12 days at the depth of 0cm.With the increase of flooding depth from-5 cm to 40 cm,tillering rate decreased.With the increase of flooding depth,the ramet height increased first and then decreased,reaching the maximum height of 61.27 cm at 7.56 cm,and the relative growth rate decreased with the increase of flooding depth.The optimum flooding depth for tuber sprouting and early growth is ranging from 3 cm to 9 cm.(3)Flooding duration and nitrogen addition had significant effects on growth characters,reproductive characters and biomass accumulation.Under the same flooding condition,plant height and leaf area increased with the increase of nitrogen supplemental concentration.The root length,specific leaf area and leaf nitrogen content showed a significant decreasing trend.Under the same nitrogen concentration,the plant height,leaf area,root length and leaf Nitrogen content of B.planiculmis seedlings increased firstly and then decreased with the increase of flooding duration,while the specific leaf area and leaf nitrogen content increased with the increase of flooding duration.The flooding duration and nitrogen addition also had significant effects on reproductive traits.Under the same flooding condition,the number of plant and corm biomass increased with the increase of nitrogen supplemental concentration.The biomass and length of rhizome first increased and then decreased.Under the same nitrogen concentration,the number of ramets,rhizome length and tuber biomass of B.planiculmis seedlings decreased with the increase of flooding duration,while the rhizome biomass increased first and then decreased with the increase of flooding duration.The significant effects of flooding duration and nitrogen addition on biomass were as follows: under the same flooding duration condition,the root-shoot ratio decreased with the increase of nitrogen addition concentration;The aboveground biomass,underground biomass and total biomass showed an increasing trend.Under the same nitrogen concentration,the ratio of root to shoot of B.planiculmi seedlings decreased firstly and then increased with the increase of flooding duration.The aboveground biomass,underground biomass and total biomass decreased with the increase of flooding duration.It can resist flooding stress through elongation and biomass distribution of aboveground and underground parts,but it is not good for long-term flooding.The addition of nitrogen promotes the growth of the plant body,and the plant is more active to take in nutrients,but the high concentration of nitrogen inhibits the growth.