A possible mechanism of mineral responses to elevated atmospheric CO2 in rice grains

Increasing attentions have been paid to mineral concentration decrease in milled rice grains caused by CO2 enrichment, but the mechanisms still remain unclear. Therefore, mineral(Ca, Mg, Fe, Zn and Mn) translocation in plant-soil system with a FACE(Free-air CO2 enrichment) experiment were investigated in Eastern China after 4-yr operation. Results mainly showed that:(1) elevated CO2 significantly increased the biomass of stem and panicle by 21.9 and 24.0%, respectively, but did not affect the leaf biomass.(2) Elevated CO2 significantly increased the contents of Ca, Mg, Fe, Zn, and Mn in panicle by 61.2, 28.9, 87.0, 36.7, and 66.0%, respectively, and in stem by 13.2, 21.3, 47.2, 91.8, and 25.2%, respectively, but did not affect them in leaf.(3) Elevated CO2 had positive effects on the weight ratio of mineral/biomass in stem and panicle. Our results suggest that elevated CO2 can favor the translocation of Ca, Mg, Fe, Zn, and Mn from soil to stem and panicle. The CO2-led mineral decline in milled rice grains may mainly attribute to the CO2-led unbalanced stimulations on the translocations of minerals and carbohydrates from vegetative parts(e.g., leaf, stem, branch and husk) to the grains.     

Direct impacts of recent climate warming on insect populations

Effects of recent climate change have already been detected in many species, and, in particular, in insects. The present paper reviews the key impacts of global warming on insect development and dispersal. The effects of climate change appear to be much more complex than a simple linear response to an average increase in temperature. They can differ between seasons and bioclimatic regions. Earlier flight periods, enhanced winter survival and acceleration of development rates are the major insect responses. Differential response of insects and hosts to warming up might also lead to disruption of their phenological synchrony, but adaptive genetic processes are likely to quickly restore this synchrony. In a number of cases, warming results in removing or relocating the barriers that limit present species' ranges. It is also likely to facilitate the establishment and spread of invasive alien species. Finally, knowledge gaps are identified and future research interests are suggested.     

呼伦贝尔岭东南旱作丘陵区气候资源潜力分析

对呼伦贝尔市阿荣旗三道沟镇商品粮生产基地主要粮食作物的光合、光温、气候、气候-土壤资源潜力进行分析,结果表明热量条件是限制该地区粮食增产的主要非可控因素,如能改善热量条件,还有20%～30%的增产潜力;该地区的降水条件对玉米、大豆、马铃薯、水稻四种主要粮食作物的满足程度在80%左右,表明降水量及其季节分布是该镇粮食产量低的制约因素之一,存在的问题是水分利用率较低;土壤养分状况对马铃薯和水稻增产未表现明显的限制作用,而对玉米和大豆增产却是最主要限制因素。     

气候变化对陇东塬区冬小麦生长发育及产量的影响

分析西峰农业气象试验站冬小麦生育期的观测资料表明,气候变暖使陇东塬区冬小麦全生育期天数缩短,主要是越冬期天数缩短,而冬小麦实际生长的天数并未缩短;气候变暖使冬小麦播种期推迟,成熟期提前,从而使麦田的休闲期延长,延长了复种作物的生长期,为提高气候资源的利用率和单位面积的产量提供了保证。气候变化对冬小麦气候产量的影响具有明显的周期性。     

新疆三工河流域气候暖湿化特征分析

对三工河流域近40a中山区、近山区、近沙漠区的气温、降水、蒸发资料进行月线性趋势分析，得出流域增温主要在2月和9月。2月增温趋势大于9月。流域春夏季气温多年变化较为稳定。降水增湿在1，2月和夏秋季节，夏秋季节降水增湿趋势大于冬季。整个流域夏季蒸发呈减小趋势，平原区蒸发减小趋势大于中山区。夏季降水增大与蒸发减小有较好的反相关性。流域冬季气候增温增湿显著，夏季增湿作用显著。各地暖湿化在空间和时间上有所差异，中山区相对较弱，平原区较强，近山平原区是气候暖湿化最为显著的地域。     

内蒙古北部荒漠草原带的严重荒漠化及其治理

位居干旱气候区的内蒙古高原中北部的荒漠草原地带 ,面临着严重荒漠化的威胁。目前已有 90 %以上的天然草场退化与沙化 ,变成寸草不生的不毛之地。大大扩展了我国北部沙尘暴频繁发生的地带 ,成为北方生态安全最危险的地区。这是多年来盲目增畜 ,超载过牧 ,滥垦乱挖的掠夺式生产经营中又加上干旱气候因素的耦合作用所造成的必然恶果。面对这一严峻形势 ,急需采取果断措施抢救荒漠草原地带的整体生态环境。应立即实行禁牧封育 ,人畜转移 ,调整结构 ,移民扩镇。使荒漠草原地带与农牧交错地带以及城市之间建立起产业化可持续发展的新途径     

甘肃第四纪气候期划分

第四纪时期气候变化是由冷和暖及干和湿组成的。冷和暖及干和湿是相对的，是呈循环变化的，是有强、弱之分和持续时间长短不同的。本文根据第四纪地层中植物孢粉和ＣａＣＯ３的含量及岩石风化系数、黄土中古土壤、第四纪泥炭的造炭期等资料，通过分析研究，用比拟方法确定第四纪气候期的性质，用冷和暖及干和湿作为第四纪气候期划分的尺度。将第四纪气候期划分为四次温暖期、五次寒冷期、一次冷热频繁交替期。     

Productive,Physiological and Biochemical Changes in Imported and Locally Born Friesian and Holstein Lactating Cows under Hot Summer Conditions of Egypt

Twenty each of healthy lactating Friesian and Holstein cows were studied. They were of similar age and body weight, nonpregnant in their third lactation and 80–100 days post partum. The investigation was carried out for 8 weeks on two farms at the same time during the hot summer season in Egypt. The first farm was in Demietta (North east of the Nile Delta, 31° 40 N) on 20 Friesian cows and the second was in Fakous (East of the Nile Delta, 30° 40 N) on 20 Holstein cows. On each of the two farms, 10 cows were newly imported and 10 were born in Egypt.The average daily milk yield and total milk production in the third lactation of the newly imported cows were significantly higher than those of the locally born cows for both Friesians and Holsteins. At the same time, the T₄, T₃, urea-N, haematological values and AST enzyme activity in the newly imported cows were significantly lower than those in the locally born ones in both breeds, while the locally born cows showed significantly lower values for rectal temperature and respiration rate, as well as for AST and Alk-P enzyme activities, than the newly imported cows of either breed.Holstein cows surpassed the Friesians in milk production, as well as thyroid hormone secretion and cholesterol, haemoglobin, packed cell volume and erythrocyte count values. The opposite was found for serum total protein, urea-N and creatinine concentrations, leukocyte count and AST, ALT and Alk-P enzyme activities.     

应用GCMs和历史气候资料生成我国在CO2倍增时的气候情景

采用3种大气环流模型(GCMs)的输出结果,并结合我国各地有代表性气象台站20-30年的逐日气象资料,在微机上生成了我国在CO_2倍增时的3种气候情景.进而分析了我国未来温度、降水和太阳辐射3要素可能的时空分布特征和季节变化趋势,并推测我国易受全球气候变化不利影响的脆弱地区.