Protective effect of butylated hydroxylanisole against hydrogen peroxide-induced apoptosis in primary cultured mouse hepatocytes

Butylated hydroxyanisole (BHA) is a synthetic phenolic compound consisting of a mixture of two isomeric organic compounds: 2-tert-butyl-4-hydroxyanisole and 3-tert-butyl-4-hydroxyanisole. We examined the effect of BHA against hydrogen peroxide (H₂O₂)-induced apoptosis in primary cultured mouse hepatocytes. Cell viability was significantly decreased by H₂O₂ in a dose-dependent manner. Additionally, H₂O₂ treatment increased Bax, decreased Bcl-2, and promoted PARP-1 cleavage in a dose-dependent manner. Pretreatment with BHA before exposure to H₂O₂ significantly attenuated the H₂O₂-induced decrease of cell viability. H₂O₂ exposure resulted in an increase of intracellular reactive oxygen species (ROS) generation that was significantly inhibited by pretreatment with BHA or N-acetyl-cysteine (NAC, an ROS scavenger). H₂O₂-induced decrease of cell viability was also attenuated by pretreatment with BHA and NAC. Furthermore, H₂O₂-induced increase of Bax, decrease of Bcl-2, and PARP-1 cleavage was also inhibited by BHA. Taken together, results of this investigation demonstrated that BHA protects primary cultured mouse hepatocytes against H₂O₂-induced apoptosis by inhibiting ROS generation.     

闽东竹阔混交林毛竹生产力研究

对闽东12年生竹阔混交林中毛竹生产力的研究结果表明:竹阔混交林比纯林具有较高的生产力,毛竹的平均胸径、平均竹高、平均竹秆产量、平均蓄积量分别比毛竹纯林增加了17.9%、8.7%、37.53%和25.6%;立竹度、均匀度、整齐度、叶面积指数均比毛竹纯林高。     

当前平原林业经营形式与农林业发展的关系

当前,邯郸平原的林业经营形式主要有集体经营、联产承包经营和单户经营等3种;这些经营形式,是与农村经济体制改革和当前生产力水平相适应的,对林业生产的发展有促进作用.本文还提出了影响林业发展的几个问题,需要加以解决。     

森林生态系统碳循环研究方法概述

介绍了森林生态系统碳循环研究方法,对当前森林生态系统碳循环研究的几种主要方法模型进行了概述,主要有Miami模型和Thornthwaite模型、Chikugo模型和生物量转换因子连续法等。     

Tree growth and stand development of four Populus clones in large monoclonal plots

Four clones of Populus were planted in replicated monoclonal plots near Olympia, WA, to evaluate their suitability for use in short-rotation culture. All clones were easily established and had minimal problems from damaging agents during the first five years. Observed differences among clones in pattern and amount of growth appeared to be associated with differences in number and density of buds, sylleptic branching, and phenology. In addition, differences in drought tolerance and stockability may also have influenced clonal differences in annual growth and stand productivity. Individual tree growth was limited by the dense 1.0-m spacing, but the best-growing clones averaged 13 to 16 m tall, 7 to 9 cm in breast-high diameter (1.3 m), and produced stand basal areas exceeding 38 m²ha^-1at 8 years. Mortality was negligible for 7 years, after which various combined effects of competition, stem borer damage (Cryptorhyncus lapathi), and a severe windstorm caused mortality ranging from 18 to 36% in the three fastest growing clones.     

Dry matter production and nutrient cycling in agroforestry systems of mandarin grown in association with Albizia and mixed tree species

A study on dry matter production and nutrient cycling in agroforestry systems of mandarin grown in association with N₂-fixing Albizia and mixed tree species (non-N₂-fixing) was carried out in the Sikkim Himalaya. A site with Albizia was referred asAlbizia-mandarin stand and the other site with mixed tree species as mandarin stand. The stand total biomass, net primary productivity and mandarin fruit production was higher under the influence of Albizia. Agronomic yield of crops remained nearly the same in both the stands. Nitrogen and phosphorus concentrations of different components of Albizia were higher than those of mixed tree species, whereas their back translocation from leaf to branch before abscission was lower inAlbizia. The mandarin-based agroforestry is a highly nutrient-exhaustive system evaluated in terms of nutrient exit through the removal of agronomic yield. This system, under the influence of Albizia, was more productive with faster rates of nutrient cycling. Nutrient use efficiency increased under the influence of Albizia, in contrary to the hypothesis that efficiency should decrease with increasing rate of uptake. The poor nutrient conservation of Albizia, and malleability of nutrient cycling under its influence make it an excellent association which promotes higher availability and faster cycling of nutrients.Albizia should be utilised more extensively in the management of mandarin-based agroforestry systems.     

桉树立地生产力与养分生产力参数的确定

桉树试验林样本分析结果表明，桉树树杆中氮，磷，钾养分浓度的倒数与养分吸收量早明显的负线性相关。基于这一相关性，对实测的数据作回归分析。估测的立地生产力极限和养分生产力参数值，以及相应的立地养分效应曲线具有较高的精确度。本文为研究林木生长和营养的动态函数关系提供了新的思路和方法。     

Quantification and Understanding of Above and Belowground Biomass in Medium Saline Zone of the Sundarbans,Bangladesh: The Relationships with Forest Attributes

ABSTRACT

The relationship between stand attributes and biomass accumulation pattern in a mangrove forest has been intensively studied in this study. We assessed above (AGM) and belowground mass (BGM) and examined the relationship between forest attributes and aboveground mass in the Sundarbans, Bangladesh. The study was conducted with 18 plots having total area of 1.08 ha. The mean AGM and BGM of the study sites were 234.08 and 132.85 Mg ha^?1 respectively. H. fomes contributed the highest amount (82.9% of total AGM and 80.53% of total BGM) of above (193.56 Mg ha^?1) and belowground mass (107.09 Mg ha^?1) at the study site. Our study revealed structural attributes (tree diameter, height, and basal area) positively correlated with AGM. In contrast, species richness and species diversity negatively correlated with AGM. Our study indicated that lack of positive relationship between species diversity and AGM which may be attributable to high AGM of the dominant species (H. fomes) and may have a considerable consequence in AGM of the study area. Thus, maintaining large trees (DBH and height) rather than species diversity in the Sundarbans mangrove forest might be an effective approach for increasing aboveground mass.     

Measuring the productivity and physical workload of brushcutters within the context of a production-based pay system

Forestry occupations are known to be physically demanding, and workers are often paid on a piece rate basis. This pay system is largely used in silvicultural treatments such as plantation and vegetation management. An ill adjusted piece rate system may induce workforce recruitment difficulties or increase accident rates and work related illnesses. A study combining work measurement, ergonomics and economics was undertaken to better understand the factors influencing a worker's workload. Mathematical relations between site factors, worker's production and heart rate variation during work have been examined based on time and motion studies of 38 brushsaw operators performing regeneration release (cleaning) in northern forests. Results show that a piece rate pay system that considers only the area treated without taking into account site factors may lead workers to behave in ways that may compromise their health and safety. The use of a pay system that integrates the influence of site factors on work performance is therefore suggested.