不同密度下樟子松非结构性碳水化合物变化规律

Changes of non⁃structural carbohydrates of Pinus sylvestris var.mongolica under different stand densities

为了解林分密度对樟子松非结构性碳水化合物(NSC)分布的影响,以39年生不同密度(490、750、1110、1550、1800、1930、2560和3520株·hm^(-2))樟子松人工林为研究对象,分析樟子松不同器官中NSC及其组分(可溶性糖和淀粉)浓度,探讨不同密度下樟子松NSC变化规律。结果表明:樟子松叶、枝和根中NSC浓度变化范围分别为50.51~82.12、58.24~76.28和13.90~56.82 mg·g^(-1)。随着樟子松林分密度增加,在490~1550株·hm^(-2)范围,新叶可溶性糖浓度降低,淀粉浓度增加,NSC浓度保持稳定;在1550~3520株·hm^(-2)范围,新叶可溶性糖、淀粉和NSC浓度均呈下降趋势。随着林分密度增加,老叶可溶性糖、淀粉和NSC浓度先增加后减少;新枝和老枝可溶性糖及NSC浓度呈先升高后下降再升高的趋势;根系可溶性糖、淀粉和NSC浓度呈先下降后上升的趋势。在林分密度为1110株·hm-2时,可溶性糖及NSC浓度在新叶和新枝较高,在老叶和老枝达到最大。该密度有利于生产更多碳水化合物,促进枝条快速生长,为成年樟子松人工林的适宜经营密度。

To understand effects of stand density on the allocation of nonstructural carbohydrates(NSC)in Pinus sylvestris var.mongolica,we analyzed concentrations of NSC and its components(soluble sugars and starch)in different organs of 39⁃yearold P.sylvestris var.mongolica monoculture with different stand densities(490,750,1110,1550,1800,1930,2560 and 3520 trees·hm^(-2)).The results showed that NSC concentrations in needles,branches and roots ranged from 50.51 to 82.12 mg·g^(-1),from 58.24 to 76.28 mg·g^(-1),and from 13.90 to 56.82 mg·g^(-1),respectively.When stand density increased from 490 to 1550 trees·hm^(-2),soluble sugars concentration of young needles decreased,starch concentration increased,and NSC concentration remained stable.When stand density increased from 1550 to 3520 trees·hm^(-2),concentrations of soluble sugars,starch and NSC in young needles showed downward trends.With the increases of stand density,concentrations of soluble sugars,starch and NSC in old needles first increased and then decreased,and concentrations of soluble sugars and NSC in young and old branches exhibited trends of increasing⁃decreasing⁃increasing,while concentrations of soluble sugars,starch and NSC in the roots first reduced and then rose.The optimal management density for mature P.sylvestris var.mongolica plantation should be 1110 trees·hm^(-2),in which concentrations of soluble sugars and NSC in young needles and branches were high and reached the maximum in old needles and branches,indicating more carbohydrate produc⁃tion and branch growth promotion.