Page 116 - 《广西植物》2020年第3期
P. 116

3 9 6                                 广  西  植  物                                         40 卷
       Abstract: As the dominant products of photosynthesisꎬ non ̄structural carbohydrate (NSC) contents can be used to indicate
       the carbon balance of plants and their adaptation strategies under environmental stresses. Three typical psammophytes at the
       fast growing stageꎬ including Casuarina equisetifoliaꎬ Vitex trifolia var. simplicifoliaꎬ Spinifex littoreus in the coast area of
       Pingtan Islandꎬ Fujian Provinceꎬ were selected and their NSC contents in leaf and stem were determined by an improved
       phenol ̄sulphuric acid method. The results were as follows: (1) Soluble sugar contents were the largest in both leaf and stem
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       of Vitex trifolia var. simplicifoliaꎬ (137.83 ± 3.75) and (90.74 ± 2.65) mgg respectivelyꎬ while starch contents were the
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       largest in both leaf and stem of Spinifex littoreusꎬ (105.41 ± 2.49) and (120.48 ± 7.67) mgg ꎬ respectivelyꎬ and NSC
       contents in above two species were all significantly larger than those in Casuarina equisetifolia (P<0.05). (2) The NSC and
       its components contents in leaf of Spinifex littoreus on the coppice dunes from rudimental periodꎬ developmental period to
       stabilized period showed no obvious trendsꎬ while decreasing trends were observed in its stem along the succession gradi ̄
       entsꎬ in which NSC and its component contents of S. littoreus on the coppice dunes in rudimental period were significantly
       larger than those in other two succession stages (P<0.05) and showed a decreasing trend. (3) From the young ̄agedꎬ mid ̄
       dle ̄aged to old ̄aged growth periodꎬ the NSC and its component contents in leaf and stem of Casuarina equisetifolia firstly
       demonstrated an increasing trendꎬ then followed by a decreasing trend. The soluble sugarꎬ starch and NSC contents in the
       leafꎬ soluble sugar and NSC in the stem of old ̄aged C. equisetifolia all suggested more significant lower contents than them
       in other two growth periods (P<0.05). (4) Species specific characteristics and its regeneration should be fully considered in
       the vegetation reestablishment in coastal sand dune ecosystemsꎬ due to the different adaptation strategies of species under
       various environmental stresses.
       Key words: non ̄structural carbohydratesꎬ soluble sugarꎬ starchꎬ psammophytesꎬ Pingtan Island

       沙生植物作为海岸沙地生态系统的重要组成                           实ꎬ适度沙埋下ꎬ单叶蔓荆( Vitex trifolia var. sim ̄

   部分ꎬ在海岸地区呈现出明显的带状分布( Maun et                       plicifolia)匍匐茎的可溶性糖和淀粉含量增高ꎬ纤
   al.ꎬ 1999)ꎬ但其成因一直存在着很多争议ꎮ 部分                      维素含量下降ꎬ匍匐茎顶端通过快速生长、不定根
   学者认为ꎬ距海远近不同ꎬ土壤盐分差异导致海岸                            形成和碳水化合物转化等来快速适应沙埋ꎮ 但重
   沙生植物形成带状分布(Sykes et al.ꎬ 1991)ꎬ但更                 度沙埋下ꎬ匍匐茎淀粉含量降低ꎬ纤维素含量升

   多研究发现ꎬ盐分胁迫对于沙生植物的影响较弱ꎬ                            高ꎬ且生长减缓ꎮ
   而沙埋可能是控制其分布的主要因素( van Puijen ̄                         平潭岛海岸沙地生境类型多样ꎬ沙生植物多样
   broek et al.ꎬ 2017)ꎮ Maun et al.(1999)认为ꎬ不同       性异常丰富ꎬ但受高温、干旱以及台风等影响(谢平

   物种耐沙埋能力各异ꎬ当沙埋超过其耐受阈值时ꎬ                            等ꎬ2001)ꎬ同一海岸不同沙生植物的生长存活状态
   某一沙生植物将会从该生境消失ꎬ从而影响不同                             往往呈现出很大差别ꎬ但其内在的生理机制尚不清
   区域的物种组成ꎬ而土壤盐分浓度极少超过植物                             楚ꎮ 本文以平潭岛海岸处于生长旺盛期的 3 个典型

   毒害水平ꎬ其可能扮演着次要角色ꎮ                                  沙生植物木麻黄(Casuarina equisetifolia)、单叶蔓荆
       海岸沙生植物在长期的盐分和沙埋胁迫下形                           和老鼠艻( Spinifex littoreus) 为研究对象ꎬ采用改进
   成了独特的适应策略ꎬ并占据一定的生态位ꎮ 非                            的苯酚-浓硫酸法ꎬ测定其叶片和茎干的 NSC 含量ꎬ
   结构性碳水化合物( non ̄structural carbohydrateꎬ简           分析不同沙生植物及同一沙生植物不同生长阶段
   称 NSC)作为光合作用的主要产物ꎬ是植物生长和                          NSC 含量的变化特征ꎬ探讨海岸典型沙生植物对于
   生理代谢的重要物质ꎬ其含量多少通常可反映植                             不同环境胁迫的适应策略及其差异ꎬ为其在不同距
   物整体的碳收支平衡关系及对外界环境胁迫的适                             海远近的优化配置提供科学依据ꎮ
   应策略(潘庆民等ꎬ2002)ꎮ 张婷凤等(2016) 研究
   发现ꎬ沙生植物通过不同器官 NSC 的转移转化ꎬ可                         1  材料与方法
   提高其抗盐耐风沙能力ꎮ 张艳琳等(2009) 研究也
   表明ꎬ随着培养液海水比例增加ꎬ海马齿( Sesuvium                      1.1 研究区概况
   portulacastrum)叶片通过提高可溶性糖和脯氨酸含                        研究区坛南湾地处福建省平潭岛东南侧ꎬ属
   量来减少盐分胁迫ꎮ 周瑞莲等(2015) 研究也证                         于南亚热带半湿润海洋性季节气候ꎬ植被以常绿
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