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1.
本文描述了采自中国江苏的环角圆Yao属Papirioides亚属一新种:苏州环角圆Yao Ptenothrix(Papirioides)suzhouensis,sp.nov.。模式标本保存在南京大学生物系。 相似文献
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Responses of nitrogen and phosphorus resorption from leaves and branches to long-term nitrogen deposition in a Chinese fir plantation 下载免费PDF全文
《植物生态学报》2018,42(9):926
为了解森林养分内循环对全球变化的响应, 基于长期模拟氮沉降试验, 研究了杉木(Cunninghamia lanceolata)人工林不同龄级(一年生、二年生和衰老)叶和枝的氮(N)、磷(P)养分分配及其再吸收特征, 并分析了不同模拟N沉降处理时间(7年和14年)杉木叶N、P养分再吸收差异。在12年生杉木中开展模拟N沉降试验, 以尿素(CO(NH2)2)为N源, 设N0、N1、N2和N3 4个处理水平, 施氮量分别为0、60、120和240 kg·hm -2·a -1, 每个处理重复3次。结果表明: (1)叶和枝在衰老过程中碳(C)、N和P含量逐渐降低, 且叶的C、N和P含量比枝高; N含量大小依次为一年生叶>二年生叶>衰老叶>一年生枝>二年生枝>衰老枝, 且N3 > N2 > N1 > N0, 而C:N则呈现相反的趋势; 衰老器官的C:N、C:P、N:P比新鲜器官高; N沉降增加了不同龄级叶和枝(除二年生叶外)的N、N:P和C:P, 但降低了P和C:N。(2)叶和枝的N、P养分再吸收率(REN、REP)随龄级的增加至衰老有规律地递减, 且REP > REN; 受长期N沉降的影响, REN叶(28.12%) <枝(30.00%), 而REP则为叶(45.82%) >枝(30.42%); 杉木叶和枝N:P与REN:REP之间存在极显著的线性相关关系。(3)随N沉降处理时间的增加, 叶REN呈降低态势, 各处理(N1、N2和N3)分别降低了9.85%、3.17%和11.71%; 而REP则明显上升, 分别增加了71.98%、42.25%和9.60%。研究结果表明: 不同器官、不同龄级的养分再吸收率随氮沉降处理的水平、处理时间而所有不同; REN:REP与N:P之间存在紧密关系。 相似文献
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本实验结果表明:衰老大鼠(26—27月龄)尾壳核多巴胺(DA)神经末梢膨体较成年组(3—4月龄)明显减少,而单个膨体内DA含量较成年组显著增多,提示纹状体DA系统在衰老过程中可能具有一定的代偿机制。本文对其意义进行了讨论。 相似文献
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《植物生态学报》2016,40(4):405
Aims
Plantations play important roles in modifying regional carbon budget and maintaining regional carbon balance. In this study, we assessed larch plantation (Larix gmelinii var. principis-rupprechtii) carbon dynamics in Weichang County from a perspective of the forest biomass-soil-wood-products chain. Our objectives were to elucidate the carbon sink capacity of larch plantation and the influences of biomass, soil and wood product pools on carbon balance.
Methods
CO2FIX model was used to evaluate the carbon storage and flow of larch plantation over a time span of 120 years. Input data for model were derived from practical investigations and published papers. We validated the simulated results and found that this model was suitable in the region and the simulated results were reliable.
Important findings
(1) Soil was the largest carbon pool for larch plantation and the wood product pool had the smallest carbon storage. Meanwhile, carbon storage in wood products gradually increased with time. (2) In a rotation of 50 years from secondary poplar-birch forest to larch plantation, 250 t C·hm-2 was sequestrated by the larch plantation. 70% of the carbon was transferred into soil in the form of litter and logging slash and the other 30% was transferred into wood products. (3) Larch plantation was a carbon sink during most of its growing period and turned to temporary carbon source when it was harvested. Larch plantation could sequestrate about 0.3 t C·hm-2·a-1 in the long term. Our results indicated the importance of wood product carbon pool in carbon dynamics of plantation, which facilitated our understanding in the carbon dynamics and capacity of plantation. 相似文献
Plantations play important roles in modifying regional carbon budget and maintaining regional carbon balance. In this study, we assessed larch plantation (Larix gmelinii var. principis-rupprechtii) carbon dynamics in Weichang County from a perspective of the forest biomass-soil-wood-products chain. Our objectives were to elucidate the carbon sink capacity of larch plantation and the influences of biomass, soil and wood product pools on carbon balance.
Methods
CO2FIX model was used to evaluate the carbon storage and flow of larch plantation over a time span of 120 years. Input data for model were derived from practical investigations and published papers. We validated the simulated results and found that this model was suitable in the region and the simulated results were reliable.
Important findings
(1) Soil was the largest carbon pool for larch plantation and the wood product pool had the smallest carbon storage. Meanwhile, carbon storage in wood products gradually increased with time. (2) In a rotation of 50 years from secondary poplar-birch forest to larch plantation, 250 t C·hm-2 was sequestrated by the larch plantation. 70% of the carbon was transferred into soil in the form of litter and logging slash and the other 30% was transferred into wood products. (3) Larch plantation was a carbon sink during most of its growing period and turned to temporary carbon source when it was harvested. Larch plantation could sequestrate about 0.3 t C·hm-2·a-1 in the long term. Our results indicated the importance of wood product carbon pool in carbon dynamics of plantation, which facilitated our understanding in the carbon dynamics and capacity of plantation. 相似文献
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落叶松人工林土壤酸度与有机磷形态的相关性 总被引:2,自引:0,他引:2
通过东北东部山地落叶松人工林不同发育阶段土壤酸度变化规律以及与有机磷形态相关关系的研究发现,不同发育阶段落叶松根际土壤水解性总酸度都高于非根际土壤,而交换性酸与总酸度的比值则相反;落叶松由幼龄林到成熟林随林龄的增大根际土壤活性酸(pH值)呈降低趋势,而非根际土壤活性酸(pH值)(除成熟林外)、根际与非根际土壤的交换性酸、土壤交换性铝、土壤水解性总酸度和交换性酸/总酸度的比值随林龄的增大呈显著增大趋势。但由于暗棕壤具有较强的缓冲性能,并且土壤活性酸(pH值)由幼龄林到成熟林随林龄的变化范围为5.27±0.25~5.93±0.12,因此,在落叶松树种适生的范围之内,不需施用石灰调节土壤的酸度。各年龄阶段森林根际土壤酸度与根际土壤有机磷形态相关密切。随着土壤潜性酸度的增加,各年龄阶段森林土壤有机磷总量、中稳性有机磷和高稳性有机磷含量降低。活性有机磷分别与活性酸、水解性总酸度呈显著正相关,其与水解性总酸度相关性随林龄的增大而降低。 相似文献
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记述了采白海南和浙江省的弹尾目疣[虫兆]科颚毛[虫兆]属Crossodonthina Yosii,2新种,海南颚毛yao C.hainana sp.nov.和天童颚毛yao C.tiantongshana sp.nov.。海南颚毛[虫兆]头部每侧有眼2个,弹器痕上有6根刚毛,非常容易与本属其它已知种类分开。天童颚毛[虫兆]与上海产的Crossodonthina tridentiens Yue&Yin,1999相似,两者的主要区别是:新种的上颚有两条长的、羽毛状分支和具5齿的片状突起,且基部齿长而细;下颚的内颚叶端部及近基部各有1齿;新种腹部第5节有3+3个疣状突起,而C.tridentiens有2+2个疣状突起;新种的爪部内侧有2个小齿,1个大齿,C.tridentiens只有1大齿。模式标本保存于上海生命科学研究院,植物生理生态所昆虫标本馆。 相似文献