Regulation Mechanisms of Stomatal Oscillation

Stomata function as the gates between the plant and the atmospheric environment. Stomatal movement, including stomatal opening and closing, controls CO2 absorption as the raw material for photosynthesis and water loss through transpiration. How to reduce water loss and maintain enough CO2 absorption has been an interesting research topic for some time. Simple stomatal opening may elevate CO2 absorption, but, in the meantime, promote the water loss, whereas simple closing of stomatal pores may reduce both water loss and CO2 absorption, resulting in impairment of plant photosynthesis. Both processes are not economical to the plant. As a special rhythmic stomatal movement that usually occurs at smaller stomatal apertures, stomatal oscillation can keep CO2 absorption at a sufficient level and reduce water loss at the same time, suggesting a potential improvement in water use efficiency. Stomatal oscillation is usually found after a sudden change in one environmental factor in relatively constant environments. Many environmental stimuli can induce stomatal oscillation. It appears that, at the physiological level, feedback controls are involved in stomatal oscillation. At the cellular level, possibly two different patterns exist： （i） a quicker responsive pattern; and （ii） a slower response. Both involve water potential changes and water channel regulation, but the mechanisms of regulation of the two patterns are different. Some evidence suggests that the regulation of water channels may play a vital and primary role in stomatal oscillation. The present review summarizes studies on stomatal oscillation and concludes with some discussion regarding the mechanisms of regulation of stomatal oscillation.     

四川人工林生态系统碳储量特征

利用森林资源清查资料和标准地实测数据估算了四川人工林生态系统的碳密度、碳储量及分配特征.结果表明:四川人工林生态系统平均碳密度为161.16 Mg C·hm^-2,各层碳密度从大到小排序为土壤层(141.64 Mg C·hm^-2)＞乔木层(17.95 Mg C·hm^-2)＞枯落物层(1.06 Mg C·hm^-2)＞灌草层(0.52 Mg C·hm^-2).四川人工林生态系统总碳储量为573.57 Tg C,其中乔木层、灌草层、枯落物层和土壤层分别为63.88、1.836、3.764和504.09 Tg C,分别占总碳量的11.14%、0.32%、0.66%和87.88%.不同人工林生态系统的碳储量和碳密度差异较大,分别介于1.21～99.44 Tg C和75.50～251.74 Mg C·hm^-2之间,其空间分配也表现为土壤层最大、灌草层最小.但四川省人工林生态系统乔木层碳密度较低,幼、中龄林分比重大,如果对现有人工林加以更好的管理,碳吸存潜力较大.从生态系统水平监测人工林生态系统的碳储量有助于提高森林碳吸存估算的精度.     

The Current Status of Bird Diversity in Yunnan Province

1IntroductionYunnanProvince,whichislocatedinsouthwestofChina(21?8'-29?8'N,97?1'-106?2'E),isgeographicallythemainpartofYunnan-GuizhouPlateau.Itstotalareaisabout383000squarekilometers.About94%ofthetotalareaaremountainousareas.Itslopesdownwardfromnorthwesttosoutheast.ThehighestpointisKageboPeakofMeliSnowMountain,atanelevationof6740m,inthenorthwestofYunnan.Thelowestpointis76.4mabovesealevelinYunjiang(RedRiver)outletofsoutheastofYunnan.YunnanProvinceiswithinthezoneofmonsoonclimateintropics…     

Quantitative assessment of acute kidney injury by noninvasive arterial spin labeling perfusion MRI:a pilot study

The kidneys are essential for maintaining homeostasis,are responsible for the reabsorption of water,glucose and amino acids,and filter the blood by removing waste.Acute kidney injury(AKI) is a syndrome characterized by the rapid loss of renal excretory function and the accumulation of end metabolic products of urea and creatinine.AKI is associated with the later development of chronic kidney disease and end-stage kidney disease,and may eventually be fatal.Early diagnosis of AKI and assessments of the effects of treatment,however,are challenging.The pathophysiological mechanism of AKI is thought to be the imbalance between oxygen supply and demand in the kidneys.We have assessed the ability of arterial spin labeling(ASL) perfusion magnetic resonance imaging(MRI),without the administration of contrast media,to quantify renal blood flow(RBF) non-invasively.We found that RBF was significantly lower in AKI patients than in healthy volunteers.These results suggest that ASL perfusion MRI,a noninvasive measurement of RBF,may be useful in the early diagnosis of AKI.     

诱变技术在作物育种中的应用

本文简述了作物诱发育种的发展现状,重点介绍了当今应用最广泛的电离辐射和化学诱变的原理其及在作物育种上的最新研究成果。     

Characteristics of dental morphology in the Xinjiang Uyghurs and correlation with the EDARV370A variant

Teeth are one of the most important materials for anthropological studies because they are likely to be preserved in ancient remains.While the frequencies of dental characteristics can provide clues to the phylogeny of populations,genetic studies at the individual level can further reveal the biological mechanisms and evolutionary context of dental characteristics.In this study,by analyzing 38 dental characteristics of 242 Xinjiang Uyghur individuals,we found that(i)the dental characteristics of the Uyghurs showed evidence of admixture between European and East Asian populations.The admixture proportions were in line with those previously reported in population genetic studies;(ii)the Xinjiang Uyghur dental characteristics formed three clusters in pairwise correlation analysis.One of the main clusters consisted of characteristics including incisor shoveling,double shoveling and mesial ridge;and(iii)all the characteristics in this cluster were significantly correlated with the genetic variant EDARV370A.The extracted composite phenotypic factor was also significantly associated with EDARV370A,which explained 18%of the total phenotypic variance.This indicated a pleiotropic effect,i.e.,the same genetic factor affects a number of dental characteristics at the same time.Our results confirmed that EDARV370A,a genetic variant that first originated in East Asia about 30000 years ago,played an important role in incisor shoveling in East Asia.This finding suggested that incisor shoveling in modern humans in East Asia is likely to have appeared after the late Pleistocene.     

Small RNAs in pollen

In plants, each pollen mother cell undergoes two rounds of cell divisions to form a mature pollen grain, which contains a vegetative cell(VC) and two sperm cells(SC). As a companion cell, the VC carries the SCs to an ovule by germinating a pollen tube. In-depth sequencing analyses of mature pollen showed that micro RNAs(mi RNAs) and short interfering RNAs(si RNAs) are present in both the VC and SCs. Additionally, epigenetically-regulated transposable elements(TEs) are reactivated in the VC and these TE m RNAs are further processed into 21-nt epigenetically reactivated si RNA(easiR NA) in SCs, which prevent 24-nt si RNA accumulation and sequester mi RNA loading. Small RNAs are thought to move from the VC to SCs, where they regulate gene expression and reinforce TE silencing. Here, we summarize current knowledge of the biogenesis and function of mi RNAs, si RNAs, and easi RNAs in pollen, emphasizing how these different small RNAs coordinately contribute to sperm cell formation and TE silencing.     

PCR方法用于奶牛早期胚胎的性别鉴定

根据牛Y染色体上的特异DNA序列合成一对引物, 通过PCR反应对奶牛早期胚胎进行性别鉴定。预测性别与移植胚胎产犊的实际性别相符率为80%。 Abstract:We have obtained the specific DNA segment from the bovine Y-chromosome and used it to design a pair of primer.The sex of embryos at the preimplantation stage have determined by using the polymerase chain reaction.10 months after uterine transfer showed that the rate of accuracy is 80%.     

AFLA技术在经济动物中数量性状位点定位上的应用

简述了AFLP分子标记的原理、方法、特点和应注意的问题,QTL检测的方法和QTL定位的策略;综述了AFLP分子标记技术在经济动物中QTL定位方面的应用现状和前景。