Spatial changes and influencing factors of fine root carbon,nitrogen and phosphorus stoichiometry of plants in China

为了研究中国陆地植物细根碳(C)、氮(N)、磷(P)的空间变化模式,揭示细根在"温度-植物生理假说"及"生长速率假说"等方面的规律,该文收集已发表的有关中国陆地植物细根研究的文献,从中提取细根C、N、P元素含量及其相关数据,分析了细根C、N、P含量及其比例与经纬度之间的关系。结果表明:细根N、P元素含量均随纬度增加而增加,P含量随经度增加而降低,N:P随经度增加而增加。细根N、P含量与年平均气温、年降水量均呈负相关关系,与土壤养分呈正相关关系。在土壤养分、温度、降水量3个非生物因素中,土壤养分对细根N、P含量的影响最大。该文中细根和粗根的C:P、N:P差异变化不完全支持"生长速率假说"。根系和叶片一样,N、P含量与纬度呈正相关关系,支持"温度-植物生理假说",反映了植物对自然环境的适应策略。     

Three‐dimensional change in temperature sensitivity of northern vegetation phenology

Understanding how the temperature sensitivity of phenology changes with three spatial dimensions (altitude, latitude, and longitude) is critical for the prediction of future phenological synchronization. Here we investigate the spatial pattern of temperature sensitivity of spring and autumn phenology with altitude, latitude, and longitude during 1982–2016 across mid‐ and high‐latitude Northern Hemisphere (north of 30°N). We find distinct spatial patterns of temperature sensitivity of spring phenology (hereafter “spring S_T”) among altitudinal, latitudinal, and longitudinal gradient. Spring S_T decreased with altitude mostly over eastern Europe, whereas the opposite occurs in eastern North America and the north China plain. Spring S_T decreased with latitude mainly in the boreal regions of North America, temperate Eurasia, and the arid/semi‐arid regions of Central Asia. This distribution may be related to the increased temperature variance, decreased precipitation, and radiation with latitude. Compared to spring S_T, the spatial pattern of temperature sensitivity of autumn phenology (hereafter “autumn S_T”) is more heterogeneous, only showing a clear spatial pattern of autumn S_T along the latitudinal gradient. Our results highlight the three‐dimensional view to understand the phenological response to climate change and provide new metrics for evaluating phenological models. Accordingly, establishing a dense, high‐quality three‐dimensional observation system of phenology data is necessary for enhancing our ability to both predict phenological changes under changing climatic conditions and to facilitate sustainable management of ecosystems.     

Biogeographical patterns in the Western Palearctic: the fasting-endurance hypothesis and the status of Murphy's rule

Aim In Europe, winter severity is positively correlated with longitude. We test how this climatic cline affects biogeographical patterns in Western Palearctic homeotherms. Location Eurasia, west of 60° longitude. Methods We test the effects of longitude on body size of carnivores, using cranial measurements of 2002 specimens belonging to 11 species. We test the effects of longitude on migration patterns of birds by comparing which populations of partial migrants are sedentary and which undergo winter migration. Results Carnivore body size does not vary consistently with longitude. Populations of partial migrants are more likely to be sedentary in western Europe and to migrate from eastern Europe than vice versa. Main conclusions Longitudinal patterns in climate exert a selective force on birds but do not affect carnivore size in a consistent, predictable manner. We find no support for the mechanism suggested to promote size change, namely the fasting‐endurance hypothesis.     

Levels of the upper forest boundary in northern Asia

On the Ural range the elevation of upper timberline changes at grade 71 m per degree of latitude in linear regression. Much lengthy cross-section—for the semi-arid regions of middle Siberia and adjacent Kazakhstan, and for the regions of eastern Siberia dominated by larch forests—exhibit parabolic regression of timberline levels upon geographic latitude. The longitudinal gradient of timberlines presumably depends on radiation balance related with the amount of precipitation. The arctic boundary of taiga in eastern Europe and Siberia lies mostly on average latitude 69° 36 E. It correlates with mean July temperature 11.2 °C, or with duration of the growing season 128 days with stable temperature of air exceeding 0°C which amounts to 876°. Daily temperatures exceeding 5° and especially 10 °C are seemingly less influential there. The value of 11.2 °C deviates by about 1 °C from the value of above 10 °C for three summer month reported by Langlet 1935, which shows the close environmental control regulating the northern and upper boundary of the northern, mostly coniferous forest on the northern hemisphere.     

浙江省主要亚热带森林群落类型物种和谱系水平的α和β多样性比较

了解不同森林群落类型的物种和谱系水平的α和β多样性, 有助于指导森林经营和生物多样性保护。本研究比较了浙江省内不同地点主要森林类型(包括常绿阔叶林、常绿落叶阔叶混交林、落叶阔叶林和针阔叶混交林)的物种α多样性和谱系α多样性, 以及物种β多样性和谱系β多样性。研究表明, 该地区主要森林类型的物种和谱系α多样性均存在较大差异, 但控制了空间和地形因子的作用后, 差异几乎全部消失; 森林类型内部及相互间的物种和谱系β多样性均存在显著差异, 同种森林类型内部的物种和谱系β多样性分别小于不同森林类型之间的物种和谱系β多样性, 且在控制了空间和地形因子的作用后, 以上差异仍然显著。本研究表明影响亚热带主要森林群落类型物种和谱系水平的α和β多样性的因素存在差异: α多样性可能主要受到空间和地形因子等的影响, 而β多样性则可能受到森林类型的重要影响。     

中国毛竹林碳氮磷生态化学计量特征

碳(C)、氮(N)、磷(P)生态化学计量比是生态系统过程与功能的重要特征, 开展种群生态化学计量学研究可以细化植物种群化学计量学内容, 确定限制植物生长的元素类型, 同时为大尺度模型的发展提供数据基础。为阐明我国毛竹(Phyllostachys edulis)林C、N、P化学计量学特征, 通过对毛竹主要产区文献数据的搜集整理与分析, 探索我国毛竹林“植物-土壤-凋落物”系统C、N、P及C:N、C:P、N:P生态化学计量特征, 以及不同组分生态化学计量特征与经纬度之间的关系。结果表明: 1)我国毛竹林叶片C含量为478.30 mg·g^-1, N含量为22.20 mg·g^-1, P含量为1.90 mg·g^-1, C:N为26.80, C:P为299.60, N:P为14.40; 毛竹林0-20 cm土层C含量为21.53 mg·g^-1, N含量为1.66 mg·g^-1, P含量0.41 mg·g^-1, C:N为14.20, C:P为66.74, N:P为4.28; 毛竹凋落物C含量为438.49 mg·g^-1, N含量为13.39 mg·g^-1, P含量为0.86 mg·g^-1, C:N为22.53, C:P为665.67, N:P为22.55。2)毛竹林“植物-土壤-凋落物”系统中, C:N表现为: 叶片>凋落物>土壤, C:P和N:P均表现为: 凋落物>叶片>土壤, 叶片N、P再吸收率分别为39.68%和54.74%, 我国毛竹林生长发育总体上可能受到P限制或者N和P两种元素的双重限制。3)纬度梯度: 叶片N含量、N:P随纬度增加而增加, C:N随纬度增加而降低。经度梯度: 叶片N:P随经度增加而增加, P含量、C:N随经度增加而降低; 土壤C:N随经度增加而增加, N含量随经度增加而降低; 凋落物N含量随经度增加而降低。4)叶片N含量与年平均气温和年降水量均存在明显负相关关系, 但对温度的响应比降水更敏感, 叶片N含量与纬度呈正相关关系, 支持“温度-植物生理假说”, 反映了植物对自然环境的适应。     

虎斑颈槽蛇多态与变异

目的研究虎斑颈槽蛇大陆亚种[Phabodophis tigrinus lateralis (Berthold)]在不同分布地区存在的多态现象和变异性。方法在分析已经报道的有关文献的基础上,研究辽宁、吉林等地野外采集到的标本,并对虎斑颈槽蛇大陆亚种的色斑变异和腹鳞的多态现象进行相关分析结果虎斑颈槽蛇大陆亚种的腹鳞数目与纬度呈强正相关,与经度呈中等正相关,与年均温度呈强负相关,与体长呈弱相关关系,年均温度高产卵时间早,而孵化时间长。结论分布范围相对较窄的蛇腹鳞数目是相对稳定的,分布范围广、跨越纬度大,腹鳞的数目差异亦很大。     

种子地理学研究的新进展

在已发表的“种子地理学”基本理论框架和内涵的基础上, 该文对种子地理学理论进行了补充和修订, 在以前提出的7个方面的研究内容基础上, 补充了土壤种子库的地理学、种子雨的地理学、种子散布方式的地理学三个方面的研究内容, 提出了“土壤种子库的三向(纬度、经度和海拔)梯度变化假说”和“种子散布模式的三向梯度变化假说”。还对以前提出的6个方面的研究内容进行了增补, 在“种子化学性状地理学”方面添加了种子稳定性同位素性状, 在“种子重量的地理学”方面添加了油质体性状, 在“种子形态性状的地理学”方面补充了种子长、种子宽、种子长宽比、种子的附属结构(如果翅的有无以及种子附属物种翅长、种翅宽、种翅长宽比)等性状, 在“花和果实的地理学”方面增添了一些新的关注对象, 如花瓣的长和宽、花萼长和宽, 还有果实的长、宽、高及其比值, 夏季成熟的果实及秋天成熟的果实比例等, 在“种子遗传学性状的地理学”方面添加了DNA含量这个性状, 在“种子细胞性状的地理学”方面增添了淀粉粒。     

Chronotype of South African adults is affected by solar entrainment

Our daily lives are influenced by three different daily timers: the solar clock, our endogenous circadian clock and the societal clock. The way an individual’s endogenous clock synchronises to the solar clock, through either advances or delays relative to sunrise and sunset, results in a phenomenon known as diurnal preference or chronotype. South Africa uses just one time zone, but in the most easterly regions of the country, the sun rises and sets up to an hour earlier than in the most westerly regions throughout the year. It was hypothesised first that South Africans living in the east of the country may have a greater preference for mornings (more morning chronotypes) than those living in the west; and second, that this difference would not be due to genetic differences in the populations, particularly a genetic polymorphism previously shown to influence chronotype. Here, we describe and compare the distribution of chorotype and PERIOD3 variable number tandem repeat (VNTR) polymorphism frequency in eastern (n = 129) and western (n = 175) sample populations. Using the Horne–Östberg Morningness, Eveningness Questionnaire we found that there was a significantly higher proportion of morning-types in the eastern population (56.6%) than in the western population (39.4%), and there were higher proportions of neither-types and evening-types in the western population (51.4% and 9.1%, respectively) than in the eastern population (37.2% and 6.2%, respectively) (p = 0.009). There were no significant differences in distribution of the PER3 genotype (p = 0.895) and allele (p = 0.636) frequencies. Although previous studies have shown associations between chronotype and PER3 VNTR genotypes, no significant associations were observed in either the eastern (p = 0.695) or the western (p = 0.630) populations. These findings indicate that, in South African populations, longitude influences chronotype independently of PER3 genotype. The impacts of the differences in chronotype whilst maintaining the same societal temporal organisation in the eastern and western regions were not assessed.