Northeast Institute of Geography and Agroecology, Chinese Academy Of Sciences
Not a member yet
4476 research outputs found
Sort by
中国自然湿地螺类生态学研究进展
No full text螺类是软体动物腹足纲的通称,是湿地生态系统大型无脊椎动物的重要组成部分。湿地螺类在维持湿地生物多样性和复杂食物网结构,保障湿地物质循环和能量流动等方面具有重要的生态功能。从基本组成、生活型、功能群方面归纳了螺类群落结构特征;分析了螺类的时空分布格局;重点讨论了影响螺类群落结构的温度、盐度、底质等非生物因子和植被、物种间影响等生物因子以及人类对螺类的影响;概述了湿地演替过程中螺类群落的变化和螺类的环境指示功能。依据目前中国自然湿地螺类的研究特点和国际研究动态,展望了未来我国螺类群落的生态学研究的重点
莫莫格扁秆藨草恢复湿地土壤种子库对长芒稗入侵的响应
No full text湿地恢复过程中,时常有外来种或本地杂草入侵。土壤种子库作为未来植被的潜在种源,对湿地恢复效果具有重要的指示意义。在莫莫格国家级自然保护区,以恢复白鹤栖息地(扁秆藨草(Scirus planiculmis)沼泽)为目的,进行了退化湿地的水文恢复;但退化湿地恢复2a后,一年生杂草长芒稗(Echinochloa caudata)在大部分区域成为建群种。以长芒稗入侵湿地和扁秆藨草自然湿地为研究对象,对比分析了长芒稗和扁秆藨草的土壤种子库及生长结实特征。结果表明,在自然湿地扁秆藨草种子库规模是长芒稗的18.42倍,而在恢复湿地长芒稗种子库大小是扁秆藨草的5.04倍。与自然湿地相比,扁秆藨草种子库密度在入侵湿地明显减少,但仍保留了一定量具有活力的种子(664.32±105.98)粒/m~2,这与研究区扁秆藨草较高的种子生产力(9210.4± 1513.4)粒/m~2及种子较强的浮力(FP50 = 39.7d)有关,说明扁秆藤草具备通过种子库或水传播恢复的潜力。长芒稗土壤种子库密度在入侵湿地高达(3345.9±520.3)粒/m~2,明显高于自然湿地种子库规模(P<0.01),说明恢复湿地受长芒稗入侵影响严重, 这与长芒稗较高的种子生产力(7621.4±376.25)粒m~2及较弱的种子浮力(FP0 = 5d)有关,同时也表明长芒稗通过水传播扩散的能力较弱。另外,研究区长芒稗平均高度超过1m,且盖度较大,不仅阻碍扁秆藨草种子的水播,也降低了到达地表的光照水平, 从而抑制扁秆藨草更新。因此,在莫莫格受长芒稗入侵湿地,于开花结实前收获长芒稗地上植物体及凋落物应是限制长芒稗扩展、同时促进扁秆藨草恢复的有效措施
钾肥施用对菜用大豆生殖生长期可溶性糖含量及产量的影响
No full text菜用大豆籽粒可溶性糖含量是评价其食用品质的重要指标,为探究钾素影响菜用大豆“源”、“库”端可溶性糖转化关系,在正常氮、磷种肥施用基础上,以菜用中科毛豆1号和品系121为材料,进行不施钾(K0)、种肥施钾120kg?hm~(-2)(K1)以及种肥施钾120kg?hm~(-2)+花期和结荚期两次喷施钾叶面肥(K2)处理,探讨植株不同部位可溶性糖积累规律。结果表明:种肥施钾显著增加菜用大豆生殖生长期(开花后4~8周)叶片、荚皮、籽粒中可溶性糖含量,在此基础上于花期、荚期两次喷施叶面钾肥有利于可溶性糖在叶片、荚皮、籽粒中的进一步积累。开花后7周(最佳采食期)时,籽粒可溶性糖含量达到最大,此时中科毛豆1号K1、K2处理相比K0处理分别高29.2% 和37.5%,而品系121分别高9.3%和24.8%。同时发现,钾肥施用显著提高了菜用大豆鲜荚采食期产量,中科毛豆1号K1、K2处理的单株鲜荚产量相比K0处理分别高8.2%和37.1%,而品系121分别高18.9% 及31.6%。钾肥施用可能通过增强菜用大豆源端(叶片)可溶性糖的供应以及促进荚皮可溶性糖的运转量而对籽粒中可溶性糖的积累起到促进作用
黑土锌有效度的物理化学研究法
No full text锌是动植物必需微量元素同时亦是污染土壤的重金属元素,研究黑土中锌形态及其有效度对保护黑土农业生态环境具有重要意义。以黑土13年长期定位试验为研究对象,采用物理化学研究法,分析评价黑土Zn形态转化及锌有效度。结果表明,长期不施肥黑土有效锌(DTPA-Zn)含量可达1.96 mg kg~(-1),长期施肥可显著增加黑土交换态Zn和无定型氧化铁结合态Zn含量,从而显著提高黑土有效Zn含量,可增至3.3 mg kg~(-1),对土壤全Zn未有明显增加;配施有机肥可显著增加矿物态Zn以外其他各形态Zn含量,土壤有效锌含量随有机肥施用量增加而逐渐增加,最高可达14.5 mg kg~(-1)。长期施肥使土壤酸化从而降低了黑土对Zn~(2+)的吸附强度和容量,且其吸附的Zn~(2+)更易解吸出来,配施一定量有机肥处理虽未能减缓土壤酸化,可在一定程度上增加土壤对Zn~(2+)的吸附强度与容量,但其吸附的Zn~(2+)更难以解吸。总体黑土有效锌含量相对较高,对Zn~(2+)吸附强度和容量均较高,但随着施肥引起土壤酸化而降低其对Zn~(2+)吸附强度和容量
内蒙古东部自然保护区天然湿地动态遥感分析
No full text为有效分析天然湿地动态变化的影响因素,该文提出了利用景观发展强度指数量化人类活动对保护区天然湿地的影响强度。以内蒙古东部2000年和2012年Landsat TM影像为数据源,运用面向对象与决策树相结合的分类方法获得各国家级湿地自然保护区土地覆盖数据,结合动态度与空间分析方法对保护区天然湿地动态变化进行分析,为湿地研究和保护提供参考。结果表明:2000~2012年间,内蒙古东部国家级湿地自然保护区内天然湿地面积呈下降的趋势,其中达赉湖自然保护区天然湿地面积减少最多;减少的天然湿地主要转变为裸地和草地,分别占湿地转化总面积的50.57%和46.22%;图牧吉和达赉湖自然保护区在2000~2012年间,受到人类活动的影响强度增大趋势最为明显;天然湿地减少是自然环境变化和人类活动共同作用的结果,自然环境变化为内因,人类活动影响是外因
不同耕作方式下土壤水分状况对土壤呼吸的初期影响
No full text以2001年在东北典型黑土上进行的保护性耕作长期定位试验下免耕、 垄作及常规耕作土壤进行了室内培养实验,按照田间持水量(water-holding capacity, WHC)的30%、 60%、 90%、 120%、 150%、 180%、 210%、 240%、 270%设定了9个水分梯度,并分别对其二氧化碳(CO_2)排放量进行了22 d的短期观测,以研究不同耕作方式下土壤水分状况对土壤呼吸的初期影响. 结果表明:①干土条件下在加水培养初期,3种耕作方式均产生了明显的激发效应,并且土壤呼吸速率与土壤含水量间存在正相关关系. ②除干旱(30%WHC)及淹水(240%WHC、 270%WHC)条件下,3种耕作方式CO_2排放通量分别为免耕>垄作>常规耕作. ③对不同耕作方式下土壤水分状况及CO_2排放通量进行了方程拟合,在30%~270%WHC条件下,免耕的CO_2排放通量与水分状况拟合为二次回归方程,而垄作与常规耕作则是线性回归方程. 在30%~210%WHC条件下,免耕与垄作下土壤CO_2排放通量与水分状况均可拟合为较好的对数方程,可决系数R~2分别为0.966、 0.956
Arabidopsis KLU homologue GmCYP78A72 regulates seed size in soybean
No full textSoybean (Glycine max) is one of the most important crops in the world, and its yield is largely determined by grain weight and grain size. However, the genes that regulate soybean seed size have not been identified. CYP78A, which is highly conserved within terrestrial plants, regulates organ development. In Arabidopsis, AtCYP78A5/KLU has been shown to determine seed size. In the present study, soybean CYP78A72 (GmCYP78A72), one of the orthologs of KLU, was over-expressed in both Arabidopsis and soybean to examine its function in plant development. GmCYP78A72 heterologous expression in Arabidopsis resulted in enlarged sepals, petals, seeds and carpel. Over-expression of GmCYP78A72 in soybean resulted in increased pea size, which is an extremely desirable trait for enhancing productivity. Moreover, knock-down of GmCYP78A72 does not reduce grain size. However, silencing of GmCYP78A57, GmCYP78A70 and GmCYP78A72 genes in triplet reduces the seed size significantly indicating functional redundancy of these three GmCYP78A genes. In conclusion, we investigated the role of CYP78A in soybean seed regulation, and our strategy can be effectively used to engineer large seed traits in soybean varieties as well as other crops
The distribution characteristics of the major capsid gene (g23) of T4-type phages in paddy floodwater in Northeast China
No full textOur previous study revealed the high diversity of the major capsid gene (g23) of T4-type phages that existed in the paddy field soils in Northeast China. In this study, the phylogeny and genetic diversity of the g23 gene in the paddy floodwater samples collected from five sampling sites at three sampling times during the rice (Oryzasativa L.) growth season in Northeast China are reported. In total, 104 different g23 clones were isolated, among which 50% of the clones exhibited the highest identities with the clones retrieved in paddy soils and upland black soils. The remaining clones had the highest identities with lake origins. Phylogenetic analysis revealed that 43% of the g23 clones grouped into three novel subgroups which included the clones unique to paddy floodwater, and no g23 sequences obtained in paddy floodwater fell into the paddy soil groups II, III, IV, V, VI, VII and NPC-A. UniFrac analysis of g23 clone assemblages demonstrated that T4-type phage communities in paddy floodwater were changed spatially and temporally, and the communities were different from those in paddy soils. Further comparison of the g23 clone assemblages from different environments demonstrated that T4-type phages were biogeographically distributed, and the distribution was both affected by geographical separation and ecological processes across the biomes
Effect of split application of nitrogen on nitrous oxide emissions from plastic mulching maize in the semiarid Loess Plateau
No full textApplying nitrogen (N) using split application to improve temporal synchronicity between crop-N demand and soil-N availability is a key strategy for improving nitrogen use efficiency (NUE). Its effect on nitrous oxide (N2O) emissions has not been well evaluated, especially from plastic mulching maize (Zea mays L.) in semiarid farmland. We conducted a two-year experiment to investigate the effect of split fertilizer N application on N2O emissions. Three approaches each applying a total of 225 kg N ha(-1) were tested either as a single application at sowing (N1), N applied with two splits at a ratio of 4:6 (N2), and N applied with three splits at a ratio of 4:3:3 (N3), a no-N application treatment was also included as a control (NO). Compared with the single application, split application of N significantly increased the grain yields by 4.7-9.1%. The cumulative N2O emissions significantly increased by 18.1% under the three splits application in the 2014-2015 season compared with the single application but not in the growing season of 2015, which followed the same pattern with yield-scaled N2O emissions. Fertilizer application combined with precipitation was the main driving factor for N2O emissions. Therefore, the higher frequency (three times) of fertilizer application had a high risk for increasing N2O emissions due to the relatively strong and frequent precipitation in maize mid and late growth period in this region; applying N with two splits is more suitable for this region which could produce higher grain yields, and lower risk of N2O emissions. (C) 2015 Elsevier B.V. All rights reserved
Interactive effects of irrigation and exponential fertilization on nutritional characteristics in Populus x euramericana cv. '74/76' cuttings in an open-air nursery in Beijing, China
No full textNutritional characteristics determine tree stock quality to a considerable extent. Exponential fertilization can induce nutrient reserves within juvenile trees, but its validity on poplar is contingent on interaction with a scientific irrigation regime due to limited water resources under global warming. In the present study, we raised 3200 Populus x euramericana cv. '74/76' cuttings under four irrigation regimes of 0 (I0), 60 % (I60), 80 % (I80), and 100 % (I100) of field capacity for soil moisture content with or without (control) the employment of nitrogen (N) addition delivered as exponential fertilization at the rate of 8 g N cutting(-1) (E8) in an open-air nursery in Beijing, China. Both height and diameter increased with the increment of soil moisture ratio or in response to exponential fertilization (EF) without any interactive effects. In general, concentrations of N, phosphorus (P), and potassium (K) declined with time in stem but foliar N concentration did not change. Under the I100 regime, EF increased foliar N concentration relative to the control but failed to affect N concentration in stem in September, when both N concentration and N content were increased by EF under the I80 regime. Stem-K content and concentration by EF under the I80 regime also increased in September, therefore EF-treated cuttings had a higher ratio of K content in stem to that in whole plant (%ANAR). Vector diagnosis for nutritional status indicated that EF resulted in dilution of K concentration but induced a steady-state P uptake in leaves under all irrigation regimes. Therefore, EF of N addition could promote N uptake to leaves of P. x euramericana cv. '74/76' cuttings, but it had a null effect on N and P reserves in stem and impaired K reserves. In conclusion, the irrigation regime of 80 % field capacity of soil moisture content was suggested for the culture of juvenile P. x euramericana cv. '74/76' cuttings. As the interactive meaning, EF was also suggested for its excellent promotion on both N and K uptakes