Comparative responses of Achillea millefolium ecotypes to competition and soil type

Summary Achillea millefolium populations from adjacent sites with zonal and serpentime soil were used to test predictions about the relation between growth and the competitive ability of plants in productive and unproductive environments. Under greenhouse conditions, individually-grown plants from both sources grew larger in serpentine soil than in zonal soil; serpentine plants accumulated 72% more biomass than zonal plants. In zonal soil, zonal plants were 71% larger than serpentine plants, although these differences were not statistically significant, and plants from both sources accumulated much less biomass and were shorter than plants growing in serpentine soil. In a high density, fertilized replacement series, zonal plants were taller and heavier but exhibited no more competitive ability than serpentine plants. The predictions that rapid height growth and biomass accumulation contribute significantly to competitive ability are not supported by our results. Although ecotypic differentiation has occurred between these A. millefolium populations, apparently in response to different soil types, the expression of these heritable differences can be masked by other environmental effects. There has been no apparent trade-off in these ecotypes between their response to the physical environment and their competitive ability.     

Peat and water chemistry at Big Run Bog,a peatland in the Appalachian mountains of West Virginia,USA

At Big Run Bog, aSphagnum-dominated peatland in the unglaciated Appalachian Plateau of West Virginia, significant spatial variation in the physical and chemical properties of the peat and in surface and subsurface (30 cm deep) water chemistry was characterized. The top 40 cm of organic peat at Big Run Bog had average values for bulk density of 0.09 g · cm^–3, organic matter concentration of 77%, and volumetric water content of 88%. Changes in physical and chemical properties within the peat column as a function of depth contributed to different patterns of seasonal variation in the chemistry of surface and subsurface waters. Seasonal variation in water chemistry was related to temporal changes in plant uptake, organic matter decomposition and element mineralization, and to varying redox conditions associated with fluctuating water table levels. On the average, total Ca, Mg, and N concentrations in Big Run Bog peat were 33, 15, and 1050 mol · g^–1, respectively; exchangeable Ca and Mg concentrations were 45 and 14 eq · g^–1 , respectively. Surface water pH averaged 4.0 and Ca⁺⁺ concentrations were less than 50 eq · L^–1 . These chemical variables have all been used to distinguish bogs from fens. Physiographically, Big Run Bog is a minerotrophic fen because it receives inputs of water from the surrounding forested upland areas of its watershed. However, chemically, Big Run Bog is more similar to true ombrotrophic bogs than to minerotrophic fens.     

福建武夷山甜槠群落能量的研究

在生物量、生产力研究基础上,对武夷山甜槠（Ｃａｓｔａｎｏｐｓｉｓ ｅｙｒｅｉ（Ｃｈａｍ ｐ．ｅｘ Ｂｅｎｔｈ．） Ｔｕｔｃｈ．）群落各组分的热值、群落能量现存量、能量年净固定量以及太阳能转化效率进行了研究。结果表明：（１）甜槠群落各组分样品的干重热值具有一定的差异,树皮热值最高,细根热值最低。（２）甜槠群落的能量现存量达７８０５８４．１ ｋＪ·ｍ － ２,其中地上部分为６７８９１３．８ ｋＪ·ｍ － ２,占总量的８６．９８％ ;地下部分为１０１６７０．３ ｋＪ·ｍ － ２,占１３．０２％ 。（３）甜槠群落的能量年净固定量（１９９２年）为２６８５６．２ ｋＪ·ｍ － ２·ａ－ １,林地太阳光合有效辐射能的转化效率为１．２９６％ 。     

The effects of liming an Adirondack lake watershed on downstream water chemistry

Calcite treatment of chronically acidic lakes has improved fish habitat, but the effects on downstream water quality have not previously been examined. In this study, the spatial and temporal effects of watershed CaCO₃ treatment on the chemistry of a lake outlet stream in the Adirondack Mountains of New York were examined. Before CaCO₃ treatment, the stream was chronically acidic. During spring snowmelt before treatment, pH and acid-neutralizing capacity (ANC) in the outlet stream declined, and NO ₃ ^– and inorganic monomeric aluminum (Al_IM) concentrations increased sharply. During that summer, SO ₄ ^– and NO ₃ ^– concentrations decreased downstream, and dissolved organic carbon (DOC) concentrations and ANC increased, in association with the seasonal increase in decomposition of organic matter and the attendant SO ₄ ^– -reduction process. A charge-balance ANC calculation closely matched measured downstream changes in ANC in the summer and indicated that SO ₄ ^– reduction was the major process contributing to summer increases in ANC. Increases in Ca²⁺ concentration and ANC began immediately after CaCO₃ application, and within 3 months, exceeded their pretreatment values by more than 130 eq/L. Within 2 months after treatment, downstream decreases in Ca²⁺ concentration, ANC, and pH, were noted. Stream mass balances between the lake and the sampling site 1.5 km downstream revealed that the transport of all chemical constituents was dominated by conservative mixing with tributaries and ground water; however, non-conservative processes resulted in significant Ca²⁺ losses during the 13-month period after CaCO₃ treatment. Comparison of substrate samples from the buffered outlet stream with those from its untreated tributaries showed that the percentage of cation-exchange sites occupied by Ca²⁺ as well as non-exchangeable Ca, were higher in the outlet-stream substrate than in tributary-stream substrate. Mass-balance data for Ca²⁺ H⁺, Al_IM, and DOC revealed net downstream losses of these constituents and indicated that a reasonable set of hypothesized reactions involving Al_IM, HCO ₃ ^– , Ca²⁺, SO ₄ ^– NO ₃ ^– , and DOC could have caused the measured changes in stream acid/base chemistry. In the summer, the sharp decrease in ANC continued despite significant downstream decreases in SO₄ ^2– concentrations. After CaCO₃ treatment, reduction of SO ₄ ^– was only a minor contributor to ANC changes relative to those caused by Ca²⁺ dilution from acidic tributaries and acidic ground water, and Ca²⁺ interactions with stream substrate.     

Responses of radial growth and stable carbon isotopes to climate in the northern Tianshan Mountains

Climate change has profound effects on forest ecosystems. Schrenk spruce (P. schrenkiana) is a natural conifer species endemic to the arid inland areas of Asia. In this study, the relationship between tree-ring parameters of P. schrenkiana and major meteorological factors were analyzed, and the main limiting factors for tree radial growth and stable carbon isotope fractionation were explored. Our results indicate that moisture stress before and during the growing season have an important influence on radial growth of P. schrenkiana, especially, the correlation coefficient between tree-ring width and vapor pressure deficit (VPD) from previous August to current July is as high as −0.622 (n = 51, p < 0.01). Collinearity analysis further supports the conclusion that the limiting factor for the radial growth of P. schrenkiana is moisture. Although the correlation analysis results show that the tree-ring δ¹³C_corr is significantly positively correlated with sunshine duration (SD), additional analysis based on first order difference variables suggests that the climate factor may not be the only limiting factor for the stable carbon isotope fractionation of tree rings in the Sayram Lake Basin. This lays the foundation for the assessment of forest management practices and carbon sink capacity in light of future climate change.     

中华鳖阴茎头的组织学观察

2021年8月,在安徽省合肥市庐江县牛王寨采集到东亚腹链蛇属(Hebius)蛇类标本1号。经形态比较发现,该蛇明显不同于大别山地区已有的东亚腹链蛇属物种——棕黑腹链蛇(H. sauteri)和绣链腹链蛇(H. craspedogaster)。分子系统学分析显示,该标本与东亚腹链蛇(H. vibakari)遗传关系最近,且形态上符合东亚腹链蛇特征,提示该标本应为东亚腹链蛇。东亚腹链蛇是安徽省和大别山地区爬行动物分布新记录种,这也是该物种在中国东北地区之外首次被报道。该分布新记录扩大了对东亚腹链蛇的分布范围的认知,对东亚腹链蛇的种群分化和生物地理学研究具有重要意义。     

中国茶渍属和石蕊属4新记录种

通过形态学及化学研究,结合nrDNA ITS序列的系统发育分析,该文报道了茶渍属(Lecanora Ach.)和石蕊属(Cladonia P. Browne)地衣4中国新记录种：莱氏茶渍(Lecanora layana Lendemer)、白头山茶渍(L. baekdudaeganensis B. G. Lee&Hur)、伪银茶渍(L. pseudargentata Lumbsch)和草皮石蕊[Cladonia caespiticia (Pers.) P. Gaertn., B. Mey&Scherb.]。该文对这些物种的分类学特征进行了详细描述,并与相似种进行了对比,同时提供了各种的地理分布图和形态图。这为中国茶渍属和石蕊属地衣物种多样性及资源利用提供了基础资料。     

湖北、河南、安徽三省大别山区地理新分布植物

湖北、河南、安徽三省大别山区地理新分布植物何家庆（安徽大学生物系合肥２３００３９）关键词大别山区,种子植物,地理新分布ＴＨＥＮＥＷＧＥＯＧＲＡＰＨＩＣＡＬＤＩＳＴＲＩＢＵＴＩＯＮＯＦＳＰＥＲＭＡＴＯＰＨＹＴＥＩＮＤＡＢＩＥＳＨＡＮＴＨＥＲＥＧＩＯＮＳ...     

云南哀牢山徐家坝中山湿性常绿阔叶林动态和节律的研究

根据多年定位观察资料,包括从组成种的种子萌发、幼苗生长及成年物种的生长规律和物候节律对湿性常绿阔叶林动态和节律的研究,结果表明：林地种子贮量、可萌发种子量和萌发种数,雨季大于旱季。幼苗生长雨季快于旱季。表明雨季是种子萌发、幼苗生长的最佳季节。立木生长是种间竞争、自我调控、自疏的过程。成年物种各物候期长、不明显与温带阔叶林各物候期短、明显不同,而开花、结果、落果终年进行与西双版纳季节雨林物候节律相似。三者的不同在于季节雨林春季（２～３ 月）落叶,常绿阔叶林冬季（１１～１２ 月）落叶,温带阔叶林秋季（９～１０ 月）落叶。依据物种物候节律特点及其对气候环境的反应区分出３ 种生态物候型：１．暖温生态物候型（占总种数（５０）的８２％ ）;２．温性生态物候型（占１２％ ）;３．温凉生态物候型（占０．６％ ）