氮磷添加对黑果枸杞(Lycium ruthenicum)营养器官非结构性碳水化合物特征的影响

Effects of nitrogen and phosphorus addition on non-structural carbohydrate properties of vegetative organs in Lycium ruthenicum

非结构性碳水化合物(NSC)在植物生长、繁殖、防御和生存等方面发挥着基础性作用。为探究黑果枸杞(Lycium ruthenicum)NSC积累的器官间规律及其对土壤氮磷供应水平的响应,以3年生黑果枸杞为对象,测定了3个氮磷比例和供应量条件下根茎叶NSC含量。结果表明:(1)黑果枸杞根、茎、叶NSC组成均以可溶性糖为主,淀粉约占37.3%;器官NSC含量粗根和细根>叶片>新梢>一二年生枝条,各器官可溶性糖含量粗根和细根>叶片>新梢>一年生枝>二年生枝;淀粉含量细根>粗根>二年生枝>一年生枝>叶片和新梢;糖淀比叶片>新梢>粗根>一年生枝>二年生枝>细根。(2)氮磷比和供应量对黑果枸杞根系可溶性糖含量无显著影响,对茎叶NSC含量的影响存在显著交互效应。氮磷比5∶1时,茎叶NSC含量随氮磷供应量升高而增加;氮磷比15∶1时,茎叶NSC含量随氮磷供应量增加显著降低;氮磷比45∶1时,茎叶NSC含量随供应量的增加而显著升高。(3)一年生枝NSC含量于萌芽前达到最大值(5.05%DW),于春梢旺盛生长期降至最低值(3.79%DW);二年生枝NSC含量在萌芽前最低(4.23%DW),于秋季落叶期达到最大值(4.33%DW)。(4)粗根和叶片NSC含量与一二年生枝NSC含量负相关;新梢NSC含量与叶片NSC、二年生枝淀粉含量正相关;一年生枝可溶性糖含量与二年生枝可溶性糖含量负相关;二年生枝淀粉含量与根系淀粉和NSC含量负相关。黑果枸杞通过调整各器官NSC积累及分配应对生长季各器官能量需求和环境氮磷供应变化,在氮磷限制环境中将更多NSC储存在根系,可平衡当前碳同化与未来能量需求的矛盾,增强个体生存能力,也为黑果枸杞应对非生物逆境胁迫提供更大的灵活性。

Non-structural carbohydrates(NSC)played a fundamental role in plant growth,reproduction,defense and survival. To explore the effects of N and P addition on NSC of Lycium ruthenicum,a field manipulation experiment combined three nutrient supply levels(Low,Medium,High)and three N:P supply ratios(5∶1,15∶1,45∶1)was conducted on three-year-old L. ruthenicum. The results indicated that:(1)Soluble sugar was the major contributor to the total NSC in different organs,starch accounts for about 37.3%. On average,the concentrations of NSC in different organs followed the order of:coarse roots & fine roots>leaves>current-year>one-year&two-year branches. The concentrations of soluble sugar,starch and the ratio of soluble sugar to starch followed the order of coarse roots & fine roots>leaves>current-year branches>one-year branches>two-year branches;fine roots>coarse roots>two-year branches>one-year branches>leaves & current-year branches;leaves>current-year branches>coarse>one-year branches>two-year branches>fine roots respectively.(2)Changes in soluble sugar,starch and NSC concentrations in different organs of L. ruthenicum. reflected significant interactions between N∶P supply ratios and supply levels. When the N∶P supply ratios was 5∶1,the NSC concentrations of leaves and branches was higher under high supply level,when the N∶P was 15∶1,the NSC and its components concentrations of leaves,current-year and one-year branches in the low supply level is significantly higher than the high supply level,when the N∶P was 45∶1,the NSC concentrations of leaves,one-year and two-year branches in high level of supply is significantly higher than low supply level. N∶P supply ratios and supply level had no significant effect on root soluble sugar concentrations.(3)The NSC concentrations of one-year branches reached the maximum value(5.05% DW)before germination and dropped to the lowest value(3.79% DW)during the shoot growth period;NSC concentrations of two-year branches decreased before germination(4.23% DW)and reached the maximum value in the foliage period(4.33% DW).(4)The NSC concentrations of coarse roots was negatively correlated with NSC concentrations of leaves、one and two-year branches;NSC concentrations of current-year branches was positively correlated with NSC concentrations of leaves and starch content of two-year branches;soluble sugar concentrations of one-year branches was negatively correlated with that of two-year branches;starch concentrations of two-year branches was negatively correlated with starch and NSC concentrations of coarse roots.When compared the impact of N and P addition on NSC concentrations of vegetative organs of L. ruthenicum,the results showed obvious organ difference adapted to N and P supply condition by adjusting accumulate and distribute NSC in different organs. Choosing to store more NSC in root system can enhance carbon balance and survivability in a nutrient-restricted environment,and also provide greater flexibility for the interaction with the non-biological environment.