Effect of slow-release iron fertilizer on iron-deficiency chlorosis,yield and quality of Lilium davidii var.unicolor in a two-year field experiment

Iron deficiency chlorosis of Lilium davidii var. unicolor is often the case in practice in alkaline soils of northwest region of China. It is difficult to control iron chlorosis because of high cost and short effective work time of conventional iron fertilizers. In this study, a 2-year field experiment was conducted to evaluate the effects of two slow-release fertilizers on the suppression of iron deficiency chlorosis, soil chemical properties, and the yield and quality of L. davidii var. unicolor. Results show that both coated slow-release iron fertilizers and embedded slow-release iron fertilizer effectively controlled iron-deficiency chlorosis. The application of slow-release iron fertilizers significantly increased plant height and chlorophyll content of L. davidii var. unicolor at different growth stages. Furthermore, coated iron fertilizer application significantly increased starch, protein, soluble sugar and vitamin C content of L. davidii var. unicolor, and it also significantly improved total amino acid content, with increases in essential amino acids(Trp, Leu, Lys, Phe, Val, and Thr contents) and in nonessential amino acids(Asp, Glu, Cit, Ihs, Acc, Ala, Pro, and Cys contents). It was concluded that application of coated slow-release iron fertilizer could be a promising option for suppression of iron deficiency chlorosis and deserves further study.     

浑善达克沙地天然沙地榆种内竞争研究

采用逐步扩大范围的方法确定影响沙地榆对象木的最佳竞争范围,利用Hegyi提出的单木竞争指数模型,对浑善达克沙地天然沙地榆种内竞争强度进行定量分析。结果表明,在沙地榆群落中,对象木的最佳竞争距离为8 m,沙地榆种内竞争强度随着植株径级的增大而逐渐减小。竞争强度与对象木胸径服从幂函数关系,从模型预测结果可知,当沙地榆胸径在30 cm以内时,竞争强度变化显著;当沙地榆胸径达30 cm 以上时,竞争强度变化很小。采用逐步扩大范围的方法能有效地确定竞争木范围,较好地反应浑善达克沙地天然沙地榆种内竞争关系。应在沙地榆胸径达30 cm前采取适当的人工疏伐措施来促进植株生长和增强生态系统的稳定性。     

造林对沙地土壤微生物的数量、生物量碳及酶活性的影响

对科尔沁沙地流动沙丘中林龄为20年左右的樟子松（Pinus sylvestris var. mongolica）和小叶杨（Populus simonii）人工林表层土壤微生物数量、微生物生物量碳和酶活性进行了研究,流动沙丘作为对照。研究表明:樟子松和小叶杨人工林可以显著改善流动沙丘土壤性状,对沙丘土壤微生物活性具有显著的促进作用;土壤微生物数量、微生物生物量碳和酶活性均表现为小叶杨林>樟子松林>流动沙丘。樟子松和小叶杨林地土壤微生物总数分别是对照的50.16倍和72.48倍,三者差异显著;樟子松和小叶杨林地土壤微生物生物量碳分别是对照的23.67倍和33.34倍,林地与对照差异显著;两种林地土壤脱氢酶、过氧化物酶、蛋白酶、脲酶、纤维素酶活性分别是对照的19.00倍和27.54倍、4.78倍和9.89倍、4.05倍和8.67倍、29.93倍和37.46倍、9.66倍和13.42倍,林地与对照差异显著。在科尔沁沙地,人工种植适合当地气候特点的乔木,不仅可以改善流动沙丘土壤性状和微生物活性,而且还能起到固定流动沙丘的目的,樟子松和小叶杨是当地值得推广种植的防风固沙树种。土壤微生物量商（Cmic∶C）是一个衡量林地土壤稳定性和有效性较好的指标,从林地土壤养分有效性、林木稳定性和可持续性等方面综合考虑,樟子松比小叶杨更具优势。     

樟子松碳汇价值的长时间尺度模拟分析（英文）

森林生态系统具有重要的碳汇作用。目前,碳汇价格可以通过碳交易、碳税和固碳项目实际成本3种机制实现。本研究从森林植被碳汇功能发挥的过程出发,认为森林植被碳汇价值包括碳固定价值和碳蓄积价值两部分。在此基础上以樟子松(Pinus sylvestris var.mongolica)为例,采用固碳项目实际成本,模拟了森林植被在100年的生命历程中碳汇价值的动态变化过程。研究表明,单株樟子松碳固定的物理量和价值量动态过程曲线都呈倒"U"型;碳蓄积的物理量和价值量动态过程曲线都近似呈"S"型。在碳固定和碳蓄积价值叠加下,碳汇价值流量过程曲线近似呈"S"型,且逐渐趋近碳蓄积价值流量曲线。100年内,樟子松的碳汇总价值(资产价值)随着林龄逐渐增大,其中碳蓄积价值所占的比重逐渐增加。樟子松林分碳汇价值曲线与单株树木的曲线不完全相同,但是基本形态一致。     

喜马拉雅冷杉和林芝云杉年轮稳定碳同位素气候意义比较

对采自西藏东南部的喜马拉雅冷杉和林芝云杉交叉定年后 ,进行了过去 1 0 0年的年轮δ13 C分析。结果表明 :冷杉和云杉年轮δ13 C序列记录了大气CO2 浓度升高引起大气CO2 的δ13 C下降的全球性趋势 ,但两者的响应程度不同。冷杉和云杉年轮δ13 C高频变化包含共同的气候环境变化信息 ,但在细节变化上存在差异。在对气候变化的响应上 ,两者记录的信息可以进行相互比较 ,以便利用不同地区不同树种的δ13 C进行大区域气候重建。     

氮饥饿细基江蓠繁枝变型和孔石莼氨氮的吸收动力学特征

以氮饥饿海藻为材料,采用多瓶法和干扰法相结合的技术,测定两种海藻在不同起始浓度下不同时间间隔内的NH₄+吸收率,对不同阶段的吸收率进行非线性回归分析,结果表明它们均符合饱和吸收动力学特征.最大吸收率和半饱和常数均随着吸收时间的延长而降低.在整个吸收过程中,吸收曲线的初始斜率变化不大,这表明在低浓度下的吸收率不受短时间快吸收的影响而保持相对的稳定.同时两种海藻相比,在相应时间内的吸收动力学参数不同,孔石莼的最大吸收率、半饱和常数和初始斜率均大于细基江蓠繁枝变型.处于氮饥饿状态的两种海藻对NH₄+-N的吸收存在以下3个时相:(1)起始短期的快吸收阶段;(2)内部营养盐浓度控制的吸收阶段;(3)外界营养盐浓度控制的吸收阶段.     

基于地图计算的流域水文过程模拟——以太湖流域上游西苕溪流域为例

本实验的目的是提取和纯化铜绿微囊藻(Microcystic aeruginosa var．major)胞外带酸性基团的多糖,为综合利用爆 发的水华提供一定的理论依据．采用 pH 8．0、80℃的热水抽提铜绿微囊藻的胞外多糖．经充分脱蛋白、脱色后用 DEAE- 纤维素(DE-52)作离子交换柱层析,分离出其中不被 DE-52吸附和被吸附的两种组分．取后者上 sephadexG-150柱进 一步分离得到两种分子量不同的酸性多糖(EAPS Ⅰ和 EAPSⅡ),质量比为1．92∶1,经 HPLC 测定 EAPS Ⅰ均分子量为7．01 ×10~4D,EAPSⅡ均分子量为4．21×10~4D．经测定,它们各带有不同含量的酸性基团：EAPS Ⅰ糖醛酸含量为10．74%, SO_4~(2-)含量为44．44μg/mg,EAPSⅡ糖醛酸含量为7．08%,SO_4~(2-)含量为9．08μg/mg．EAPSⅠ单糖组成为：9．6549%D( ) 木糖,19．2522% D-果糖,71．0930%葡萄糖;EAPSⅡ单糖组成为：6．4065%D( )木糖,18．0016%D-果糖,75．5919%葡萄糖．     

中国太湖物理—生物工程实验中菱对水质影响的模式

A model on a physico-biological engineering experiment for purifying water in Wulihu Bay of Lake Taihu by using Trapa natans var. bispinosa was constructed. The state variables in water in the physico-biological engineering were ammonium nitrogen (NH₄⁺-N); nitrate nitrogen (NO₃^--N); nitrite nitrogen (NO₂^--N); phosphate phosphorus (PO₄^3--P); dissolved oxygen (DO); nitrogen (N) and phosphorus (P) in detritus; biomass density, N and P in phytoplankton and in Trapa natans var. bispinosa, N and P in the substance adsorbed by the membrane of the engineering and the rootstocks of Trapa natans var. bispinosa. The state variables in bottom mud layer were PO₄^3--P in the core water,exchangeable P and N. The external forcing functions were solar radiation, water temperature, NH₄⁺-N; NO₃^--N; NO₂^--N; PO₄^3--P; N and P in detritus; DO; phytoplankton concentrations in inflow water and the retention time of the water in physico-biological engineering channel. The main physical, chemical and biological processes considered in the model were:growth of Trapa natans var. bispinosa and phytoplankton; oxidation of NH₄⁺-N and NO₂^--N, of detritus break down; N and P sorption by the enclosure cloth of the experimental engineering and by the rootstocks of Trapa natans var. bispinosa in water; reaeration of water; uptake of P, NH₄⁺-N, NO₃^--N by phytoplankton and Trapa natans var. bispinosa:mortality of the phytoplankton and Trapa natans var. bispinosa:settling of detritus; and nutrient release from sediment. Comparison of calculated results and observed results showed that the model was constructed reasonably for the experiment. The mechanism of purifying lake water in the experiment engineering was discussed by the use of the model.     

呼伦贝尔草原沙漠化土地的综合整治区划

呼伦贝尔草原的沙漠化土地现在多处于由级向级发展的阶段,有很大的发展潜力和危险性,必须对其进行综合整治。其主要成因是过度放牧,过度放牧不仅直接使砂质草原发生沙漠化,而且还严重影响天然樟子松的天然更新和扩展,因此必须对放牧进行科学的规划和管理。作者遵循地带性和非地带性相结合原则、发生学原则、主导性原则、与已有的相关区划相统一原则,把呼伦贝尔草原划分为2个综合整治亚区和5个综合整治小区,并提出了相应的综合整治对策。     

Effects of the spread of the alga Caulerpa racemosa var. cylindracea on the sponge assemblage from coralligenous concretions of the Apulian coast (Ionian Sea, Italy)

The present work investigated the modifications induced by the spread of the green macroalga Caulerpa racemosa var. cylindracea (Bryopsidales, Chlorophyta) on the sponge assemblage of Apulian coralligenous concretions (Ionian Sea – Torre Ovo, Italy). The study of qualitative and quantitative sponge composition was carried out before (2004) and after (2006) the spread of this invasive alga by means of traditional (quadrat scraping) and photographic sampling methods. Results indicate that the spread of the green alga is concomitant with a significant decrease in percentage sponge cover both on horizontal- and on vertical-oriented substrates. In addition, strong modifications to the structure of the community in terms of repartition of the available substrate have been observed since the algal spread. Conversely, no major changes have affected the specific composition of the sponge assemblage, suggesting that at this stage of colonization the algal spread has not produced a loss of sponge biodiversity. However, there is a clear need to monitor closely the C. racemosa invasion to verify its long-term impact on the sponge assemblage.