Allometric models for estimation of aboveground biomass of Gmelina arborea Roxb. in pulpwood plantations of Bangladesh

Gmelina arborea Roxb. is a fast-growing, deciduous tree species native to Bangladesh. It has been widely planted since 1992 for commercial production of pulpwood in hilly areas of Bangladesh. The purpose of this study was to derive well-fitting allometric models for estimation of aboveground biomass, and carbon and nutrient (nitrogen, phosphorus and potassium) stocks in G. arborea to ensure sustainable production and management of this species. Eight linear models with 64 regression equations were tested for estimation of aboveground biomass, carbon and nutrient stocks in different parts (leaves, branches, bark and stem) of the plant. The best-fitting allometric models were selected in accordance with various relevant statistical criteria.     

10龄及14龄中国鲎和圆尾鲎头胸甲宽度与体重的回归分析

为了研究鲎形体与体重之间的关系,进一步探讨其生长特性,分别测定了中国鲎(Tachypleus tridentatus)和圆尾鲎(Carcinoscorpius rotundicauda)14龄成鲎和10龄幼鲎及不同性别的形态参数(头胸甲宽度及体重)。结果表明,中国鲎和圆尾鲎14龄成鲎和10龄幼鲎以及雌、雄的头胸甲宽度与体重均表现为正相关(R20.88);10龄中国鲎和圆尾鲎异速生长曲线的斜率-回归系数b分别为2.2263和2.1883,而14龄成鲎的回归系数b分别为3.1551和2.6501;10龄和14龄雌、雄中国鲎的b值分别为2.2314(♀)、1.9626(♂)和3.2295(♀)、2.8674(♂),10龄和14龄雌、雄圆尾鲎的b值分别为2.5342(♀)、1.9547(♂)和2.7791(♀)、2.1803(♂),b值均大于1,表明体重增长率大于头胸甲宽度的增长率,处于正生长期,且雌鲎的异速生长率均大于雄鲎;F检验表明,中国鲎和圆尾鲎10龄及14龄不同性别的头胸甲宽度与体重存在极显著的线性关系(P0.01)。     

Altitudinal patterns of stand structure and herb layer diversity of Picea schrenkiana forests in the central Tianshan Mountains,Northwest China

Altitude is a useful indicator to examine patterns of forest structure and species diversity in relation to environmental factors.In this study,the altitude patterns of forest stand structure and species diversity were analyzed across 20 plots in the Tianchi Nature Reserve,Northwest China.The results showed that mean stem height(Hm),maximum stem height(Hmax) and mean stem diameter at breast height(Dm) of Picea schrenkiana trees all decreased significantly with increasing altitude.Potential tree height(H*) decreased while stem taper increased significantly as altitude increased,suggesting remarkable altitudinal changes in biomass allocation between the diameter and height growth of Picea schrenkiana.Understory herbaceous richness increased significantly with increasing altitude,or with decreasing total basal area(TBA),Hm and stand volume(Volume).High light availability for understory herbs might account for the higher species richness at high altitude.Sorensen Index decreased significantly with the increase in altitude intervals,while the Cody Index demonstrated a converse pattern,suggesting greater differences in species composition with larger distances.     

海南清澜港杯萼海桑生态系统碳密度及分配特征

采用Komiyama红树林异速生长模型,对海南清澜港杯萼海桑生态系统的植被生物量、碳密度及其空间分布特征进行研究。结果表明:杯萼海桑植被层总生物量为(177.89±14.36)t·hm^-2,碳密度为(80.35±6.92)t·hm^-2,其中,乔木层生物量为(176.52±14.23)t·hm^-2,碳密度为(79.69±6.86)t·hm^-2,占林分植被层总碳密度的99.2%。杯萼海桑生态系统总有机碳库密度为(536.91±54.99)t·hm^-2,其中0~105 cm土壤碳密度为(456.56±48.07)t·hm^-2,占总碳贮量的85.0%,植被有机碳密度占总碳贮量的14.85%,林下植被层和现存凋落物层仅占0.15%。     

松嫩平原不同生境芦苇生殖分株的异速生长分析

通过乳熟后期大样本随机取样,对松嫩平原季节性积水的单优种芦苇群落和旱地生境羊草+芦苇群落的芦苇生殖分株数量特征进行了定量分析。结果表明,2种生境除花序长和花序生物量外,分株高、构件生物量、分株生物量、生殖生长比率和构件生物量分配间均达到显著差异。2种生境绝对数量性状中花序生物量变异系数最高,分别为57.73%和49.87%;相对数量性状中生殖分配的变异系数最高,分别为36.17%和39.44%。株高与花序长呈正相关,但与生殖生长比率呈负相关趋势。在构件生物量分配关系中,生殖分配和生产分配、生产分配和茎生物量分配均呈极显著的幂函数异速生长关系。揭示了不同生境条件下芦苇较强的调节生殖分配能力,体现了植物个体生长与生殖策略。     

A Power Function Based Approach for the Assessment of the Sulfate Deprivation Impact on Nutrient Allocation in Young Maize Plants

Thirteen-day-old maize (Zea mays L.) plants were exposed hydroponically to sulfur (S)-deprivation and their nutritional status was monitored for ten days. Sulfur (S) -deprivation altered the allocation of nutrients between roots and shoots in a differential manner and the effect was approached in terms of a power function. The experimental curvature was analyzed through the value of the exponent of the function and two formulations of the approach were tested through regression analysis. In the shoot, the impact of the S-deprivation relative to that on dry mass was: calcium (Ca) (45.3%) > nitrate (NO₃) (18.9%) > magnesium (Mg) (17.2%) > manganese (Mn) (14.1%) > water (W) = phosphorus (P) = potassium (K) = iron (Fe) = copper (Cu) > nitrogen (N) (?4.3%) > ammonium (NH₄₎ (?4.7%) > zinc (Zn) (?12%) > boron (B) (?21.4%) > S (?75.2%). In the root, the relative impact was: N = K = Ca = Zn = B > P (?12.7%) > NO₃ (?14.7%) > NH₄ (?18.4%) > W (?27.8%) > Mn (?34.4%) > Mg (?37.5%) > Fe = Cu (?40.5%) > S (?126.6%). Both models produced the same conclusions.     

Relationship between metabolic rate in vitro and body mass in a marine teleost,porgy Pagrus major

The rate of oxygen consumption of minced whole body was determined volumetrically, as an indication of metabolic rate in vitro (M _{in vitro} ), at 20°C in porgy Pagrus major ranging from 0.0002 g (just after hatch) to 2.9 g (67 days old) in body mass. A triphasic relationship was found between M _{in vitro} of individual fish (l.min^–1) and wet body mass W (g). During the prolarval stage accompanied with the transitional period to the postlarval stage (0.00020–0.00023 g, 0–6 days old), the mass-specific metabolic rate in vitro (M _{in vitro} /W in l.g^–1.min^–1) increased with age (D in days) as expressed by an equation M _{in vitro} /W = 3.88 + 0.74/D. During the postlarval stage (0.00031–0.003 g, 8–22 days old), M _{in vitro} /W remained almost constant, independent of body mass following an equation M _{in vitro} /W = 5.24 W^–0.085. During the juvenile and adolescent stages (0.0047–2.9 g, 30–67 days old), M _{in vitro} /W decreased with increasing body mass following an equation M _{in vitro} /W = 1.66 W^–0.235. These results correspond with the triphasic relationship between metabolism in vivo and body mass observed in intact porgy of 0.0002–270 g (Oikawa et al. 1991). It is concluded, therefore, that the dependence of mass-specific metabolic rate on body size exists in vitro as well as in vivo, during the early stages in the porgy. Based on these results, factors controlling the metabolism-size relationship are discussed.     

干旱和灌溉条件下少花蒺藜草分株生物量分配特征

调查了生长在科尔沁沙地干早、灌溉2个条件下的少花蒺藜草(Cenchrus pauciflorus)分蘖丛.对分株高度、分株生物量以及根、茎、叶、穗、叶鞘等构件生物量进行了定量统计分析.结果显示,灌溉条件下,植株高度为41.2 cm.明显高于干旱条件的33.7 cm.灌溉条件下果穗生物量是干旱环境下的1.8倍.2种条件下...     

Genetic parameters for different growth scales in GIFT strain of Nile tilapia (Oreochromis niloticus)

Body weight, length, width and depth at two growth stages were observed for a total of 5015 individuals of GIFT strain, along with a pedigree including 5588 individuals from 104 sires and 162 dams was collected. Multivariate animal models and a random regression model were used to genetically analyse absolute and relative growth scales of these growth traits. In absolute growth scale, the observed growth traits had moderate heritabilities ranging from 0.321 to 0.576, while pairwise ratios between body length, width and depth were lowly inherited and maximum heritability was only 0.146 for length/depth. All genetic correlations were above 0.5 between pairwise growth traits and genetic correlation between length/width and length/depth varied between both growth stages. Based on those estimates, selection index of multiple traits of interest can be formulated in future breeding program to improve genetically body weight and morphology of the GIFT strain. In relative growth scale, heritabilities in relative growths of body length, width and depth to body weight were 0.257, 0.412 and 0.066, respectively, while genetic correlations among these allometry scalings were above 0.8. Genetic analysis for joint allometries of body weight to body length, width and depth will contribute to genetically regulate the growth rate between body shape and body weight.     

Generalized allometric volume and biomass equations for some tree species in Europe

Since biomass is one of the key variables in ecosystem studies, widespread effort has aimed to facilitating its estimation. Numerous stand-specific volume and biomass equations are available, but these cannot be used for scaling up biomass to the regional level where several age-classes and structural types of stands coexist. Therefore simplified generalized volume and biomass equations are needed. In the present study, generalized biomass and volume regression equations were developed for the main tree species in Europe. These equations were based on data compiled from several published studies and are syntheses of the published equations. The results show that these generalized equations explain 64–99% of the variation in values predicted by the original published equations, with higher values for stem than for crown components.