覆土厚度及土壤水分对五角枫种子萌发及幼苗生长的影响

Effect of Covering Soil Thickness and Soil Water Content on Seed Emergency and Seedling Growth of Acer mono

种子覆土厚度及土壤水分供应量是影响其萌发和幼苗建成的关键生境因子。通过室内控制实验,研究了不同覆土厚度(0、1、2、4、6、8、10 cm)及土壤相对含水量(4%、8%、12%、16%、20%、30%和40%)对五角枫种子萌发特征、幼苗早期生长及生物量分配特性的影响。结果表明,五角枫种子出苗率随覆土厚度增加呈先增后降趋势。当覆土厚度为1~2 cm时,出苗率显著高于其他处理(P<0.05);覆土厚度≥4 cm时抑制出苗;覆土10 cm时种子无法出苗。覆土厚度增加对幼苗高生长表现出明显抑制,幼苗总茎长、主根长以及鲜重随覆土厚度增加呈下降趋势,幼苗根茎比及地径则呈先降后增趋势。随土壤相对含水量升高,五角枫种子出苗率呈先增加后降低趋势。当土壤相对含水量为4%时,种子能够萌发出苗,但出苗率低(59.26%);当土壤相对含水量由8%提高到30%,种子出苗率由67.78%提高为85.19%,且出苗较整齐,其中土壤相对含水量为30%时种子出苗率显著高于其他处理;当土壤相对含水量提高到40%时,过高的土壤水分又导致出苗率下降。水分条件对五角枫幼苗早期生长具有显著影响,随土壤相对含水量的升高,幼苗株高、主根长、基径、幼苗鲜重均表现出显著增加趋势。综上所述,对五角枫种子覆土1~2 cm并保持土壤相对含水量30%,其种子出苗率高且出苗整齐,幼苗生长健壮。

Seed covering soil thickness and soil water availability are key habitat factors affecting germination and seedling establishment.This paper investigated the response of different thickness covering soil(0,1,2,4,6,8 and 10 cm)and soil moisture(4%,8%,12%,16%,20%,30%and 40%)on seed germination characteristics,early seedling growth and biomass allocation of Acer mono through controlled indoor experiments,in order to provide theoretical references for the seedling cultivation.The results showed that seedlings emergence rate of A.mono increased first and then decreased with the increase of covering soil thickness.When the thickness covering soil was 1-2 cm,the seeding emergence percentage was significantly higher than other treatments(P<0.05);seedling emergence was inhibited when thickness of covering soil was≥4 cm,and seedlings did not occurred at the covering soil thickness of 10 cm.With the increase of covering soil thickness,seedling height growth was significantly inhibited,and seedling total stem length,main root length and fresh weight tended to decrease with increasing soil thickness,while seedling root/shoot ratio and ground diameter tended to decreases and then increase.The seedling emergence rate increased and then decreased with the increase of soil relative water content.When the relative soil water content was 4%,the seeds could germinate but the seedling emergence rate was low(59.26%).When the soil relative water content was increased from 8%to 30%,the seedling emergence rate increased significantly from 67.78%to 85.19%,and the seedlings emerged neatly,in which the seedling emergence rate was significantly higher than other treatments when the soil relative water content was 30%.When the soil relative water content increased to 40%,the excessive soil moisture led to a decrease in seedling emergence.The total stem length,main root length,basal ground diameter and fresh weight of seedlings all showed a significant increase with the increase of soil relative water content.In conclusion,the seeds of A.mono were covered 1-2 cm soil and maintained at 30%relative soil water content,which resulted in a high seedling emergence rate and healthy seedling growth.