The influence of chemical factors on the selectivity of Pinus resinosa stumps for Fomes annosus

Compounds such as resins or phenols produced by the host in response to wounding or fungal penetration may play an important role as factors of resistance against Fomes annosus. By extracting stem sections, that were kept for different intervals in a closed chamber, with different organic solvents chloroform produced the most inhibitory extractives against F. annosus. This may explain at least partially the decreasing stump selectivity for F. annosus. Three compounds were isolated from the neutral fractions of chloroform extractives from 24 days wounded wood discs which were found to be different from the compounds in normal and 12 days fractions. Spectrophotometric analyses reveal some characteristics of these isolated compounds, whereas their chemical formula and structure need further investigation.     

Thermal properties of interior decorating material and the sensation of cold/warm by contact II: the relations among heat flux, temperature change of material, and sensation of cold/warm by contact

The main purpose of this study was to investigate the changes in heat flux and temperature after the subject's palm was in contact with interior decorating materials. The relations among heat flux, temperature, and sensation of cold/warm during contact were studied. Ten men and ten women were selected and introduced to 21 materials for the contact test. They were in contact with the specimens for 30min without seeing them in a climate-controlled room at 25°±1°C and 65% RH. Changes in the heat flux and temperature of the specimens were determined by a heat flux meter. A sensory evaluation test was applied to evaluate the cold-warm contact. Results indicated that the heat flux and temperature increased with increasing time after the subject's palm was in contact with the specimens. The heat flux (Q ₃₀) and temperature (T ₃₀) 30min after the subject's palm contacted the specimens were greater for male subjects than for female subjects. A positive linear regression equation existed between the values for Q₃₀ andT ₃₀, whereas a negative linear regression formula existed the sensation of cold-warm by contact (5) and the values of ln(Q ₁·). Therefore, the sensation of cold/warm by contact could be estimated simply by using the thermal physical properties of the interior decorating materials.Part of this report was presented at the International Conference on Effective Utilization of Plantation Timber, Chi-Tou, Taiwan, ROC, May 1999     

Evaluation of the level of threat and protective classification of the vegetation of Makehe Forest in Sanjiangyuan Nature Reserve, west China

After investigating and studying the vegetation, we have established that Makehe Forest, in Sanjiangyuan Nature Reserve, Qinghai Province, is host to a total of 364 different species, representing 173 “genera” in 55 different vegetative families. We propose five quantifiable indices for evaluating the level of threat to these plants: 1) the distribution frequency of the “line transect”; 2) the distribution frequency of sample plots; 3) the distribution density inside sample plots; 4) the existing abundance in the forest region; and 5) plant fidelity. The results show that there are two endangered species, six vulnerable species, 12 nearly threatened species and 344 safe species. The study tried to evaluate the urgency for conserving these plants, according to coefficients of closeness to disappearance, of genetic loss and of usefulness. Results also showed that the number of species of primary concern is two; of secondary concern, nine; of the third level, 23; and of least concern, 330 species. __________ Translated from Journal of Beijing Forestry University, 2006, 28(3): 20–25 [译自: 北京林业大学学报]     

二氧化氯应用于水厂消毒的优缺点

本文作者根据二氧化氯自身特点及在水厂中的实践,论述了二氧化氯的主要物理性能,消毒氧化作用,制取方法,以及在水厂消毒中的应用。     

木荷种子贮藏方法试验初报

对木荷种子进行低温冷藏和常温贮藏试验。结果表明：低温冷藏7个月、常温贮藏8个月的种子发芽率分别为20．8％和3．8％，t检验结果为两种处理的木荷种子发芽率差异极显著。说明不同的贮藏方法对木荷种子的发芽有显著的影响。     

管氏肿腿蜂防治双条杉天牛试验

在贵州省普定县的人工柏木林内,利用管氏肿腿蜂进行了防治危害柏木的双条杉天牛幼虫的试验。每0.67 hm2柏木林分别施放1 500头和2 000头管氏肿腿蜂,1个月后寄生率分别为62.1%和67.7%;并表明其为一项环保有效的防治措施。     

湿地松等20个树种种子射线造影技术研究

应用软Ｘ射线仪对湿地松等２０个树种种子进行衬比造影和直接造影技术研究，找出了各树种种子不同焦片片距（３００ｍｍ和２００ｍｍ）不同感光材料（Ｘ光胶片、普通胶片、相纸）的最适电压、电流和曝光时间，以及最适衬比剂、衬比浓度和衬比时间．     

Plant antifreeze proteins and their expression regulatory mechanism

Low temperature is one of the major limiting environmental factors which constitutes the growth, development,productivity and distribution of plants. Over the past several years, the proteins and genes associated with freezing resistance of plants have been widely studied. The recent progress of domestic and foreign research on plant antifreeze proteins and the identification and characterization of plant antifreeze protein genes, especially on expression regulatory mechanism of plant antifreeze proteins are reviewed in this paper. Finally, some unsolved problems and the trend of research in physiological functions and gene expression regulatory mechanism of plant antifreeze proteins are discussed.     

Seasonal variations in photosynthesis of Picea morrisonicola growing in the subalpine region of subtropical Taiwan

From January 1999 to May 2001, we investigated seasonal variations in the photosynthetic capacity of Taiwan spruce (Picea morrisonicola Hay.) growing in the subalpine region of subtropical Taiwan (23 degrees 29' N, 120 degrees 53' E, 2600 m a.s.l.). Photosynthetic capacity (near light-saturated net photosynthetic rate, Pnsat, chlorophyll fluorescence (Fv/Fm) and soluble protein concentration of needles all increased from mid or late spring to early winter. Even when minimum air temperature of the measuring day dropped to near 0 degrees C, Pnsat remained at about 20% of the highest value observed in winter. There was a curvilinear relationship between Fv/Fm and the minimum or mean air temperature of the measuring day. The increase in Fv/Fm with temperature was slowed when the daily mean air temperature was above 7 degrees C, or the minimum air temperature was above 3 degrees C; however, when air temperatures dropped below these values, Fv/Fm varied sharply. Seasonal variations in Pnsat paralleled those in Fv/Fm and needle soluble protein concentration. In early or mid spring when air temperature and Fv/Fm increased, Pnsat and soluble protein concentration remained low. Multiple regression analysis showed that seasonal variations in Pnsat were affected by Fv/Fm, air temperature and needle soluble protein concentration, and the multiple regression equation could be used to estimate Pnsat in different seasons. We conclude that the decrease in photosynthetic capacity of Taiwan spruce in winter and its subsequent recovery in spring were mainly caused by photoinhibition and its reversal, and changes in needle soluble protein concentration. Another possible explanation for the delayed recovery of photosynthetic capacity in spring may be associated with the slow increase in needle soluble protein concentration.