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---

板式定量输送机链传动系统驱动力的计算方法

为提高板式定量输送机启动和加速时运行的稳定性和安全性,对链传动系统的驱动力的计算问题进行了研究。采用逐点计算法求得链传动系统稳定运行工况下的最大静张力,提出采用多轴电力拖动系统的折算方法,将直线移动部分和旋转部分的惯性阻力折算到驱动轴得出加速载荷,由最大静张力和加速载荷确定最大驱动力。结果表明,加速载荷约为最大驱动力的35%,计算驱动功率及破断力时除考虑保持运行的最大静张力外,必需考虑加速载荷的影响

Modbus communication access control method based on rule self-learning

本发明公开了一种基于自学习规则的Modbus通信访问控制方法，该方法基于Netfilter/iptables技术架构，采用数据包深度解析技术实现了对工业控制系统中Modbus通信协议的深度解析，完成Modbus主站与Modbus从站之间数据通信的访问控制；工作于Modbus?TCP/IP网络，支持TCP和UDP两种传输协议；具有自学习规则功能，通过设置自学习时间和自学习门限，实现对Modbus访问控制规则的自动生成。本发明可以检测和防范Modbus通信过程中的异常行为，保障工业控制系统的可靠性与安全性

Security defense module of Modbus TCP communication based on region/enclave rules

针对目前工业控制系统中新型工业病毒的入侵检测难点问题,分析Modbus通讯协议的设计缺陷,提出Modbus TCP通讯深度解析方法,通过对Modbus应用层协议的关键字段的解析,有效应对来自协议应用层的威胁。在此基础上,提出Modbus TCP通讯的安全规则描述的一般形式,并进一步提出基于入侵检测规则和&quot;白名单&quot;相结合的工业SCADA系统中Modbus TCP通讯安全防御模型,通过定义不同区域间正常通讯的最小集合,极大程度上消除系统存在的风险敞口,通过及时报警兼顾可能合法但可疑的通讯流量。仿真实验验证了该方法的有效性

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位于伊犁河谷东端的巩乃斯河源区,是新疆乃至中国西北地区降水最为丰富的地区之一。利用位于巩乃斯河源区的雪岭云杉树轮宽度资料,分析了树轮宽度对山区气候要素的响应关系,发现制约树木径向生长的主要因子仍然是水分条件。利用一元线性回归模型建立树轮宽度标准化年表与巴音布鲁克站和天山积雪雪崩站上年7月到当年6月降水平均值的转换方程,重建了这一区域150年来的降水变化历史,该转换方程的方差解释量达到55.8%,较好地通过了统计检验,重建降水序列与伊犁地区旱灾历史记录吻合。对150年降水序列的变率特征分析表明,降水变率在1910年前后明显增大,表明极端降水事件发生频率增加。研究区降水变化趋势与整个天山山区的降水变化趋势一致,但没有记录20世纪20年代发生在我国北方大范围的干旱事件

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..

书法心理治疗对震后210名小学生创伤后应激反应的心理干预

发掘文化资源中的灾后心理干预方法,验证具有中国文化特征书法治疗的有效性.方法 采用香港大学高尚仁教授创立的书法治疗方法对德阳地区2所小学的80名四、五年级有明显创伤后应激反应的小学生进行对照实验.实验组41名学生,对照组39名学生.研究在地震后1年进行.实验组每天进行书法练习,每次完成5页的定量训练;对照组正常上课,实验为期30天.以事件冲击量表(儿童版CRIES-13)问卷、唾液皮质醇分别作为筛选和干预效果指标.结果 干预结束后,实验组唾液皮质醇和CRIES阳性指标显著下降,对照组差异不显著.结论 书法治疗能有效缓解创伤后应激反应,是一项值得推广的心理干预方法