寂漠千秋 福祉万代

沙漠是指沙质荒漠，有时也广义地包括沙地。在中国“雄鸡”状版图的颈背处，是我国广袤的西北干旱区。在那里至西向东串珠状地横亘着温带沙漠和草原沙地。沙漠日照强烈，降水稀少，气候干燥!沙漠里泥土稀薄，基质疏松，土壤贫瘠!沙漠里多大风，风运沙移，沙暴肆虐!沙漠历来被人类视为生存的艰难之处，甚至禁区!     

“绿色革命”新进展:赤霉素与氮营养双重调控的表观修饰助力水稻高产高效育种

以半矮秆育种为代表的“绿色革命”极大地提高了作物产量,但也带来氮营养利用效率降低的严重问题。“绿色革命”主要基于调控赤霉素的代谢和信号转导而实现。前期的研究发现,赤霉素信号转导关键因子DELLA蛋白通过调控GRF4而负调控氮素的吸收利用,为半矮秆品系氮利用效率低的问题提供了解决方案。最近的一项研究进一步揭示了GA信号途径与氮响应交叉互作的新机制。该研究发现水稻(Oryza sativa)NGR5是氮素调控分蘖数目的一个关键基因,其表达受氮诱导。通过招募PRC2,NGR5对D14和OsSPL14等分蘖抑制基因所在位点进行H3K27me3甲基化修饰,从而抑制其表达。而在半矮秆背景下超表达NGR5可以提高低氮水平下的水稻产量。NGR5同时也被发现为赤霉素受体GID1的一个新靶标,受到其负调控。该研究发现了调控赤霉素信号通路的新机制,并对高产高效的新一代“绿色革命”育种实践具有重要启示。     

海岸护林卫士—火炬松

火炬松(Pinus taeda)又名台大松,原产美国南部,在原产地树高可达30米左右。该树种喜温暖湿润的气候,能耐干燥瘠薄的土壤;具有很强的抗松毛虫和松干蚧的特性,对海风和海雾也有较强的抗性。我国安徽、江苏、浙江、福建、广东和江西等省均已广泛引种。火炬松一般在3月下旬开始     

美国《化学文摘}2009年引文频次最高的1000种期刊表公布-〈现代生物医学进展〉名列第234位

据中国高等学校自然科学学报研究会与中国科学技术期刊编辑学会最近发布的信息显示：     

杉木种子败育过程中核酸,蛋白质和类脂含量的变化（简报）

杉木种子败育过程中形成的涩籽含有较多的单宁类和凝集素类物质。败育前期核酸、蛋白质、类脂及DNA,RNA的含量较少,而有胚种子中此类物质的含量则随着胚的发育不断上升。     

Effects of grazing intensity and grazing exclusion on litter decomposition in the temperate steppe of Nei Mongol,China

Aims Grazing intensity and grazing exclusion affect ecosystem carbon cycling by changing the plant community and soil micro-environment in grassland ecosystems. The aims of this study were: 1) to determine the effects of grazing intensity and grazing exclusion on litter decomposition in the temperate grasslands of Nei Mongol; 2) to compare the difference between above-ground and below-ground litter decomposition; 3) to identify the effects of precipitation on litter production and decomposition. Methods We measured litter production, quality, decomposition rates and soil nutrient contents during the growing season in 2011 and 2012 in four plots, i.e. light grazing, heavy grazing, light grazing exclusion and heavy grazing exclusion. Quadrate surveys and litter bags were used to measure litter production and decomposition rates. All data were analyzed with ANOVA and Pearson’s correlation procedures in SPSS. Important findings Litter production and decomposition rates differed greatly among four plots. During the two years of our study, above-ground litter production and decomposition in heavy-grazing plots were faster than those in light-grazing plots. In the dry year, below-ground litter production and decomposition in light-grazing plots were faster than those in heavy-grazing plots, which is opposite to the findings in the wet year. Short-term grazing exclusion could promote litter production, and the exclusion of light-grazing could increase litter decomposition and nutrient cycling. In contrast, heavy-grazing exclusion decreased litter decomposition. Thus, grazing exclusion is beneficial to the restoration of the light-grazing grasslands, and more human management measures are needed during the restoration of heavy-grazing grasslands. Precipitation increased litter production and decomposition, and below-ground litter was more vulnerable to the inter-annual change of precipitation than above-ground litter. Compared to the light-grazing grasslands, heavy-grazing grasslands had higher sensitivity to precipitation. The above-ground litter decomposition was strongly positively correlated with the litter N content (R² = 0.489, p < 0.01) and strongly negatively correlated with the soil total N content (R² = 0.450, p < 0.01), but it was not significantly correlated with C:N and lignin:N. Below-ground litter decomposition was negatively correlated with the litter C (R² = 0.263, p < 0.01), C:N (R² = 0.349, p < 0.01) and cellulose content (R² = 0.460, p < 0.01). Our results will provide a theoretical basis for ecosystem restoration and the research of carbon cycling.     

多视角谈生态摄影

林路：唯美背后的责任,沈孝辉：生态摄影三要素,张砥生：重要的是“拍什么”和“怎么拍”,孙曾田：必须不断追问“为什么”,庄孔韶：兼收并蓄避免“硬伤”,李皓：最直接的公众教育手段,     

日本发明大量培养人体胚胎干细胞新方法

科技日报东京5月31日报道：日本理化学研究所的一个研究小组日前找到了一种能够抑制细胞“自杀”的技术，由此开发出一种大量培养人体胚胎干细胞的新方法，这一成果有望应用于未来的干细胞研究。[编者按]     

Carbon cycle of larch plantation based on CO2FIX model

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.     

高考生物学热点问题浅析

高考热点问题，指的是那些对社会影响大、几乎人所共知、易被学生接受的与生物学知识有关的内容。高考热点问题的题材具有时效性强、影响面广等特点。如克隆羊、人类基因组计划、细胞周期蛋白的发现等。