施用氮、磷对油松幼苗叶形态与解剖结构的影响

Effects of nitrogen and phosphorus application on needle morphological and anatomical structure in Chinese pine seedlings

施用氮和磷素对油松生长有一定的促进作用,为进一步了解其对针叶形态与解剖结构的影响,采用田间小区实验,设置4种处理,即对照(不施氮和磷)、施氮(+N,每次20 kg/hm^2,连续施用7次,下同)、施磷(+P,每次10 kg/hm^2)及氮磷共施(+NP,每次N 20 kg/hm^2+P 10 kg/hm^2),对油松当年生针叶开展研究.结果显示:施氮、施磷或氮磷共施增加了油松的地径、冠幅和地上部生物量,施氮或磷后叶氮或磷含量显著增加.对叶长、宽、厚和表面积施氮影响不大但施磷显著增加.施氮显著增加了叶中柱和转输组织的面积及所占比例,而施磷显著增加了表皮层、树脂道腔、中柱、转输组织、木质部和韧皮部的面积,同时树脂道腔、中柱和转输组织面积所占横截面积比例也有显著增加.施氮影响22个形态和解剖结构参数中的4个,而施磷对14个参数都有显著影响,表明施磷对油松针叶形态和解剖结构的影响大于施氮.主成分分析表明施磷主要影响光合和树脂生产能力,而施氮或施磷均增加了转输组织功能.本研究表明磷是油松幼苗生长的主要限制因子,因此生产实践中要重视磷肥的使用.

Nitrogen and phosphorus are the major nutrients that affect vegetation growth and productivity, and their rational application can promote the growth of Chinese pine seedlings; however, their effects on the needle morphology and anatomical structure are unclear. The effects of nitrogen and phosphorus application on the morphological and anatomical traits of current-year needles in Chinese pine seedlings were studied through four treatments with seven applications per treatment： CK （no fertilizer use）, N application （＋ N, 20 kg/hm^2 per application）, P application （＋ P, 10 kg/hm^2 per application）, and both N and P application （＋ NP, 20 kg/hm^2 N ＋ 10 kg/hm^2 P per application）. The results showed that the application of nitrogen, phosphorus, or nitrogen and phosphorus increased the stem diameter, crown size, and aboveground biomass. Nitrogen or phosphorus application increased current-year needle nitrogen or phosphorus content significantly. Nitrogen application had little effect on the length, width, thickness, and surface area of the current-year needles; however, phosphorus application increased the needle length, width, thickness, and surface area. Nitrogen application significantly increased the area and the proportion of the central cylinder as well as the transfusion tissue of current-year needles, whereas phosphorus significantly increased the surface area of the epidermis, resin duct cavities, central cylinder, transfusion tissue, xylem, and phloem, and proportion of the resin duct cavities; the central cylinder and transfusion tissue also increased significantly. Nitrogen application affected 4 of 22 morphological and anatomical structure parameters, whereas phosphorus application had an obvious influence on 14 of 21 parameters, indicating that phosphorus application had a stronger effect on the needle morphology and anatomical structure than nitrogen application. Principal components analysis showed that phosphorus application mainly stimulated photosynthesis and resin production, and nitrogen or phosphorus application increased the function of the transfusion tissue. These results suggest that phosphorus is the major limiting factor for the growth of Chinese pine seedlings, and that phosphorus application should be highlighted in practice.