硝态氮供应水平对棕榈幼苗根系形态及苗木生长的影响

Responses of Root Morphology and Seedling Growth of Trachycarpus fortunei to Different Nitrate Supply Level

采用沙培盆栽试验,研究不同硝态氮水平下棕榈(Trachycarpus fortunei)幼苗根系形态的适应性变化及其对幼苗生长及养分吸收的影响。结果表明:处理50 d,缺氮时根系生长最好,缺氮处理诱导了根系生长;处理100、150 d时,低氮处理根系生长较好,缺氮处理根系生长速度减缓,养分缺失限制了根系生长的增加,施氮处理根系生长速度增加。3个处理期,随着施氮浓度的增加,根和地上部分N质量分数显著上升;相同施氮浓度处理下,随着处理时间的延长,不施氮处理根和地上部分N质量分数显著降低,低中氮处理根中N质量分数显著下降,地上部分N质量分数较稳定,高氮处理根中N质量分数较稳定,地上部分N质量分数显著上升。3个处理期,根中P质量分数差异均不显著,处理100、150 d时,高氮处理地上部分P质量分数最高,随着处理时间的延长,不施氮和低中氮处理下根和地上部分P质量分数显著下降,高氮处理下,根和地上部分P质量分数差异不显著。3个处理期,地上部分K质量分数随着供氮浓度的升高而增加,不同处理时间,相同供氮水平下,根和地上部分K质量分数较稳定。处理100 d时,7.5 mmol·L-1硝态氮处理根系生长最好,棕榈幼苗生物量的增加和养分的积累量最高。

A sand culture experiment was established to study the response of root morphology of Chinese Windmill Palm seedlings under different NO-3-N levels(0, 7.5, 15 and 22.5 mmol·L-1, respectively, denoted by N0, N1, N2 and N3) and their effects on seedling growth and nutrient absorption, and to provide a reference for improving palm seedling quality and optimizing seedling fertilization management techniques. The root growth was best under nitrogen deficiency at 50 d since the cultivation. At 100 and 150 d, the root growth was better under low nitrogen treatment, the root growth rate was slowed under nitrogen deficiency treatment, nutrient deficiency limited root growth, and the root growth rate increased under nitrogen application. In three treatment periods, with the increase of the NO-3-N application, the N content in the root and above-ground parts increased significantly. With the treatment time extension, the N content in roots and above-ground parts decreased significantly under no nitrogen treatment. Under 0 and 7.5 mmol·L-1 NO-3-N treatment, the N content in roots decreased significantly, and the N content in above-ground parts was stable. Under high-nitrogen treatment, the N content in roots was stable, and the N content in above-ground parts increased significantly. There was no significant difference in root under three treatment periods. At 100 and 150 d, the P content in the above-ground part of the high-nitrogen treatment was the highest. With the extension of processing time, the P concentration in the root and above-ground part was significantly reduced, and under high-nitrogen content treatment, there was no significant difference in P concentration in roots and above-ground. In the three treatment periods, K concentration in above-ground increased with the increase of NO-3-N supply. At the same NO-3-N level, the K concentration in roots and above ground was relatively stable with the extension of processing time. At 100 d, root growth was the best under 7.5 mmol·L-1 NO-3-N application, and biomass and nutrient accumulation were the highest in Chinese Windmill Palm seedlings.