塞威氏苹果树台形态特征及梯级变化

选择以西天山野果林为例,应用徕卡TS06无合作目标性全站仪(Reflectorless Total Station)获取野苹果林树台的形态参数数据,定量分析西天山野苹果林树台的三维形态特征和空间分布格局,构建野苹果林树台的DEM(数字高程模型Digital Elevation Model,DEM),对野苹果林树台微地貌景观状况进行研究。结果表明:(1)研究区的野苹果树台的形态比较规则,长宽比为0.657 9～1.431 0,差异比较小,呈扇形或半圆形。且能够明显看出野苹果树所在的位置(即样地中心)颜色较深,且突出,高程值较大。(2)坡度、底径与野苹果林树台的底面积、表面积、体积、长、宽、高、长宽比都呈现出显著相关性。其中,野苹果林树台的坡度与树台的高和长度之间呈现出明显的线性正相关性,R^2分别为0.96、0.90;树台的底径与其底面积、表面积、长度呈现出较明显的线性相关,R^2分别为0.61、0.46、0.47。其研究结果可为合理利用森林植被,水土保持,以及野苹果树根部营养储存量提供一定的理论支持。

吉林架树台湖湿地公园退化湿地修复对策及建议

本文介绍了吉林架树台湖湿地公园的基本概况和湿地退化状况,并从湿地生态补水、渠系改造和修复、水域清淤、珍稀水鸟及栖息地生境保护与修复等方面提出了湿地修复的对策及建议。

Concentrations of foliar and surface soil in nutrients Pinus spp. plantations in relation to species and stand age in Zhanggutai sandy land, northeast China

The concentrations of the foliar and surface soil nutrients and the variation with species and stand age were studied inPinus spp. plantations in Zhanggutai area, northeast China. The results showed that the total N, total P and C: N ratio of the soil inP. sylvestris var.mongolica stands were significantly higher in comparison with those inP. tabulaeformis andP. densiflora stands. ForP. sylvestris var.mongolica, the foliar P concentration appeared to decrease with age, and the foliar N and K concentrations did not show a consistent change with age. As for the different tree species of the similar age, the foliar N and P concentrations were significantly different (p<0.05), being withP. sylvestris var.mongolica>P. densiflora>P. tabulaeformis. The foliar N: P ratio ofP. densiflora significantly was higher thanP. sylvestris var.mongolica andP. tabulaeformis, while the foliar K was no obvious difference between the three tree species. There were significant correlation (p<0.05) between soil total N and P, soil organic matter and total P, foliar N and P, but it did not show significant correlations between soil and foliar nutrient concentrations, which might attribute to the excessive litter raking, overgrazing and low soil moisture in this area. Based on the foliar N: P ratio, we introduced a combination threshold index of N: P ratio with their absolute foliar nutrient concentrations to determine the possible limiting nutrient. According to the critical N: P ratio and their absolute foliar N, P concentrations, theP. sylvestris var.mongolica stands showed a decreased N limitation degree with age, theP. densiflora stands showed unlimited by N and P in the whole, and theP. tabulaeformis stands showed co-limited by N and P. No significant difference in soil nutrient concentrations of the surface soils was found between 45, 29, 20-yr-oldPinus sylvestris var.mongolica plantation stands. Keywords coniferous trees - foliar nutrient concentration - limiting nutrients - N - P ratio - Zhanggutai sandy land CLC number S718.55 Document code A Article ID 1007-662X(2004)01-0011-08 Foundation item: This research was supported by Key Knowledge Innovation Project (KZCX3-SW-418) of Chinese Academy of Sciences.Biography: CHEN Guang-sheng (1978-), male, master candidate in Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, P. R. ChinaResponsible editor: Song Funan

Effects of Organic Fertilizer on Fruit Quality and Acidified Soil Chemical Properties in Yantai Orchard

[Objective] This study aimed to investigate the improving effect of organic fertilizer on acidified soil as well as their effects on fruit quality and quantity in Yantai orchard.[Method] Plot experiment was conducted to investigate the effects of organic fertilizer on fruit yield and quality of Red Fuji and chemical properties of acidified soil.[Result] The apple yield in acidified soil applied with organic fertilizer all increased.Under the application of biological organic fertilizer,the apple yield was higher,and it was 8.92% higher than that in the control group.Under the mixed application of chemical fertilizer and biological organic fertilizer,the growth and development of apple trees were improved,and the total soluble solid(TSS) content,vitamin C(Vc) content and TSS-acid ratio in mature apples all increased.The application of organic fertilizer significantly reduced soil acidity.Compared with those in the control group,the soil p H value,organic matter content and alkali-hydrolyzable nitrogen content under the application of biological organic fertilizer were increased by 8.33%,15.10% and 30.80%,respectively.[Conclusion] The application of biological organic fertilizer could improve the yield of apple in acidified soil.

Dendrimer-based strategies for cancer therapy:Recent advances and future perspectives

This review reports some recent advances on the use of dendrimer-based systems for cancer therapy. Dendrimers are emerging as promising carriers or stabilizers for drugs and nanoparticles（NPs） due to their highly branched 3-dimensional globular shape, internal hydrophobic cavity and multiple peripheral functional groups. The fabricated nanoplatforms loaded with therapeutic agents such as drugs,siRNAs or NPs can be further modified to have targeting specificity, antifouling properties and good biocompatibility.In particular, recent advances in the surface modifications of dendrimers and the application of dendrimers as versatile platforms for different therapeutic treatments to cancer including chemotherapy, radiotherapy, photothermal therapy,photodynamic therapy, gene therapy, and combination therapy will be introduced in detail.