氮素调控对草地早熟禾解剖结构及组织碳氮含量的影响

Effects of nitrogen regulation on the anatomical structure,carbon and nitrogen contents in tissues of kentucky bluegrass

采用控制变量法,即控制单一变量(霍格兰德培养液中氮素的浓度),用不同氮素浓度培养液进行植物培养,取其典型部位制作成石蜡切片,观察、测量、分析解剖结构各指标之间的差异,并测定总氮、总碳含量,研究氮素调控下解剖结构及C/N的变化规律。结果表明:15 mmol/L高氮处理的草地早熟禾,其叶、茎、根颈中的表皮厚度、厚壁组织长度、气腔面积、维管束面积等指标数值均与中氮、低氮有显著差异,高氮各组数据均大于其他两组。当氮素浓度为15 mmol/L时,利于草地早熟禾解剖结构的发育。随着氮素浓度增加,叶、茎、根颈3个部位的总氮、总碳含量呈现上调趋势,相同氮处理下草地早熟禾不同部位的C/N为根颈>茎>叶。

The aim of the current study is to use Poa pratensis as a model plant to study the impact of nitrogen nutrition on its anatomical structure and carbon and nitrogen contents（ C/N） in different tissues in order to clarify the relationship between anatomical structure,carbon and nitrogen contents and nitrogen adaptation. In this study,control variate method（ a single variable： concentration of nitrogen in Hoagland＇s culture solution） was applied. Plant medium of different nitrogen concentrations was used,paraffin sections were made from representative parts of the plant. Differences between the indices of the anatomical structures were observed,measured and analyzed. In addition,the total nitrogen and total carbon contents were also quantified to investigate the rule in the nitrogen-mediated changing of the anatomical structure and C/N of P. pratensis. The results showed that the thickness of the epidermis and thick-walled tissue,the air cavity area,and the area of the vascular bundle in the leaves,stems,and root collar in the 15 mmol/L high nitrogen treatment group of P. pratensis as well as other parameters were all significantly different from those in medium and low nitrogen levels. The parameters of each group in the high nitrogen group were higher than those in the other two groups. When the nitrogen concentration reaches 15 mmol/L,the development of anatomical structures of P. pratensis was significantly improved. With the increase of nitrogen concentration,the contents of total nitrogen and total carbon in three parts（ leaves,stems and root collar） were up-regulated. The C/N ratio in different tissues of Poa pratensis treated with the same amount of nitrogen were arranged as follows： root collar stem leaves.