Tannins and Nutrient Conservation Strategies of Casuarina equisetifolia in Coastal Protection Forest

短枝木麻黄是滨海沙地上重要的防护树种。本研究以福建东山和惠安沿海防护林短枝木麻黄为对象，解析了短枝木麻黄不同部位单宁的结构，系统探讨了两个群落类型（短枝木麻黄纯林和短枝木麻黄厚荚相思混交林）以及不同发育阶段短枝木麻黄养分保存策略的差异；在短枝木麻黄正常和衰败林中进行凋落小枝分解实验，阐明凋落小枝分解过程中单宁和养分水平的动态变化，并运用数学模型拟合凋落小枝的分解规律，分析了单宁与养分之间的关系。研究结果表明： （1）运用高效液相色谱（HPLC）和MALDI-TOF质谱技术分析了短枝木麻黄小枝、树皮和细根单宁的组成成分，结果表明，短枝木麻黄小枝单宁主要由棓酸和鞣花酸组成，而树皮和细根提取物的组...Casuarina equisetifolia is an important wind break shelter tree in coastal sandy areas. This study on Casuarina equisetifolia in Dongshan and Huian of Fujian province, discussed the differences of nutrient conservation strategies between two communities (mono-specie forests and mixed forests with A. crassicarpa) and among different development stages of C. equisetifolia. The changes in tannins and...学位：理学博士院系专业：生命科学学院生物学系_植物学学号：2172008015039

Dynamics of tannin concentration and nutrient resorption for branchlets of Casuarina equisetifolia plantations at different ages

通过对福建省惠安县不同林龄短枝木麻黄人工林不同发育阶段小枝单宁含量及氮磷再吸收率的研究,探讨了短枝木麻黄林分发育过程中的营养保存策略。结果表明,幼龄林(5年生)成熟小枝中的总酚(TP)、可溶性缩合单宁(ECT)总缩合单宁(TCT)含量及蛋白质结合能力(PPC)显著高于成熟林(21年生)和衰老林(38年生)。随着林分发育,成熟小枝中n含量显著升高,而P含量呈降低趋势。不同发育阶段林分成熟小枝中n∶P比均大于20,且随着林龄的增加而升高。磷再吸收率(PrE)显著高于氮再吸收率(nrE),均以成熟林分最高。这表明短枝木麻黄小枝单宁含量与养分再吸收受林龄影响,其养分保存机制会随着林分生长发育的变化而进行调节。Casuarina equisetifolia is characterised by high primary productivity in coastal sandy soils,which are generally low in nutrient contents.High tannin production and nutrient resorption may be important strategies for C.equisetifolia in coastal environments.Despite the widespread planting and known ecological and physiological properties of C.equisetifolia,there is scant information about the nutrient resorption patterns and tannin concentrations for branchlets of C.equisetifolia plantations during stand development.Since plant ecophysological traits are associated with ageing,tannin content and nutrient resorption efficiency could change with stand development.Therefore,tannin level and nutrient resorption of C.equisetifolia at different developmental phases(juvenile,mature and senescent) were examined to evaluate possible nutrient conservation strategies under nutrient limitation in Huian County,Fujian Province.The results showed that total phenolics(TP) contents,which were in the order juvenile stand > senescent stand > mature stand for senescent branchlets and decreased from 218.52 to 180.49 mg / g during stand development for mature branchlets,decreased during branchlet senescence in all stands.The extractable condensed tannin contents(ECT) in mature and senescent branchlets of C.equisetifolia were juvenile stand > senescent stand > mature stand.The ECT contents of C.equisetifolia increased during branchlet senescence both in the mature and senescent stands but decreased in the juvenile stand.The protein-bound condensed tannin(PBCT) contents of branchlets increased during senescence in juvenile and mature stands and remained the same in senescent stand.The fibre-bound condensed tannins(FBCT) of branchlets increased during senescence in mature stand and did not change in juvenile and senescent stands.Total condensed tannin(TCT) followed similar pattern as ECT during stand development.Protein precipitation capacity(PPC) in mature and senescent branchlets were significantly higher in juvenile stand than in mature and senescent stands.PPC decreased during branchlet senescence in the three stands.Significant positive linear correlations were found between PPC and TP or TCT.Nitrogen(N) concentrations both in mature and senescent branchlets obviously increased during stand development.Phosphorus(P) concentrations in mature branchlets were similar in juvenile and mature stands but lower in senescent stand.Phosphorus concentrations in senescent branchlets of juvenile stand were significantly higher than those of mature and senescent stands.Nitrogen: phosphorus ratios(N ∶P ratios) of mature branchlets,were all above 20,also increased during stand development.Nitrogen resorption efficiencies(NRE) in three stands were basically below 50%,the lowest in senescent stand.Phosphorus resorption efficiencies(PRE) were above 70% with the highest in mature stand(78.08%).There were significant negative correlations between N and P concentrations in mature and senescent branchlets.Nitrogen resorption efficiency had a particular strong relationship with the N ∶P ratios of branchlets.On the other hand,PRE was not significantly related to N ∶P ratios of branchlets.There were significant correlations between TP or TCT and N or P concentrations in branchlets except for the relationship between TCT and P concentrations in senescent branchlets.The above results indicated that the tannin level,nutrient concentration and resorption were affected by stand age.C.equisetifolia could adjust their nutrient conservation with stand development at intraspecific level.国家自然科学基金项目(41201293;41176092); 国家“十一五”科技支撑计划项目(2009BADB2B0302); 国家林业局南方山地用材林培育重点实验室和福建省森林培育与林产品加工利用重点实验室资助项

Contents of Some Mineral Elements and Their Resorption Efficiencies in Casuarina equisetifolia Branchlets Across a Coastal Gradient

对福建东山赤山林场不同海岸梯度上短枝木麻黄小枝中的钾(k)、钙(CA)、镁(Mg)、钠(nA)、铁(fE)、锰(Mn)和锌(zn)元素含量及其再吸收率动态进行了研究.结果表明,海岸梯度对短枝木麻黄小枝中各元素含量及其再吸收率均具有显著影响.在各海岸梯度上,k再吸收率为正值,且基干林带的再吸收率显著低于其它样地,fE和zn为负值,CA、Mg和nA再吸收率在防护林带前沿为负值,而在后沿林为正值,Mn则相反.这表明,基干林带严重的环境胁迫显著降低了短枝木麻黄小枝的养分再吸收率.短枝木麻黄成熟小枝中的k、Mg含量与其再吸收率存在显著正相关,而nA和fE与其再吸收率存在显著负相关,其它元素与其再吸收率之间没有显著相关性.除k外,各元素在衰老小枝中的含量与相应元素再吸收率之间均存在显著负相关,表明元素再吸收程度越高,其再吸收率就越高.CA、Mg、nA和fE再吸收率之间具有显著的正相关关系(P<0.01),zn除与Mn再吸收率呈显著正相关外,与其它元素均表现为负相关,Mn则与其它元素再吸收率之间没有显著相关性.因而短枝木麻黄小枝中不同类型的养分状况对其再吸收率具有不同的影响.表5参42Contents of some mineral elements and their resorption efficiencies in Casuarina equisetifolia branchlets across a coastal gradient were studied at the Chishan Forestry Center of Dongshan County,Fujian Province,China.The results showed that the distance to coast had a significant effect on the contents of mineral elements and their resorption efficiencies.Resorption efficiencies of K element(REK) were all positive across the coastal gradient,with the lowest value found at the coastline sampling site,while Fe and Zn resorption efficiencies(REFe and REZn) were all negative across the coastal gradient.Ca,Mg and Na resorption efficiencies(RECa,REMg and RENa),which were contrary to Mn(REMn),were negative in seaward plantations and positive in inland plantations.It was suggested that the resorption efficiencies of the mineral nutrients significantly decreased with severer environmental stresses.There were also significant positive correlations between the K and Mg content and their resorption efficiencies in mature branchlets while the correlations between the Na and Fe content and their resorption efficiencies were significantly negative.In senescent branchlets,the content of all the elements and their resorption efficiencies except for K were negatively correlated.In addition,the correlation was positive between REZn and REMn,while negative between REZn and resorption efficiencies of other elements.No correlation was found between REMn and resorption efficiencies of other elements.These results showed that nutrient conditions in branchlets had different effects on their resoption efficiencies for different mineral nutrients.Tab 5,Ref 42国家“十一五”重大科技支撑计划项目(No.2009BADB2B0302)资助---

不同林龄短枝木麻黄小枝单宁含量及养分再吸收动态

通过对福建省惠安县不同林龄短枝木麻黄人工林不同发育阶段小枝单宁含量及氮磷再吸收率的研究,探讨了短枝木麻黄林分发育过程中的营养保存策略。结果表明,幼龄林(5年生)成熟小枝中的总酚(TP)、可溶性缩合单宁(ECT)总缩合单宁(TCT)含量及蛋白质结合能力(PPC)显著高于成熟林(21年生)和衰老林(38年生)。随着林分发育,成熟小枝中N含量显著升高,而P含量呈降低趋势。不同发育阶段林分成熟小枝中N∶P比均大于20,且随着林龄的增加而升高。磷再吸收率(PRE)显著高于氮再吸收率(NRE),均以成熟林分最高。这表明短枝木麻黄小枝单宁含量与养分再吸收受林龄影响,其养分保存机制会随着林分生长发育的变化而进..