持续干旱下天山野生杏幼苗渗透调节物质的累积特性

以新疆伊犁地区的4类野生杏(野生甜仁杏1号、野生甜仁杏2号,野生苦仁杏1号、野生苦仁杏2号)为材料,研究其在干旱胁迫下渗透调节物质的积累特性.对二年生天山野杏苗进行持续80 d的田间自然干旱处理过程中,每隔20 d取样分析土壤相对含水量(SRWC)及叶片相对含水量(LRWC),Na+,K+和可溶性蛋白质、可溶性糖以及脯...     

Influence of Degree of Hydrolysis on Chemical Composition,Functional Properties,and Antioxidant Activities of Chinese Sturgeon (Acipenser sinensis) Hydrolysates Obtained by Using Alcalase 2.4L

Protein hydrolysates from Chinese sturgeon were prepared using Alcalase 2.4L enzyme. Under the optimum conditions (enzyme–substrate ratio of 3.5%, pH of 8.5, and temperature of 55°C), the degree of hydrolysis (DH) was 13.8%, 16.7%, and 19.1% after 1, 3, and 6 h, respectively. The contents of crude protein and amino acid increased at DH of 19.1% to 86.97% and 78.29%, respectively. There was an obvious increase in the low-molecular-weight peptides, which could enhance the hydrolysate’s functional properties such as solubility, representing more than 90% at different pH levels. The obtained protein hydrolysates revealed good emulsification properties and high oil absorption. Furthermore, good antioxidant activities such as 1, 1-diphenyl-2-picrylhydrazyl (DPPH) inhibition, ferric reducing power, and ferrous ion (Fe²⁺⁾ chelating ability were attained depending on the solution concentration. The findings indicate that the functional and antioxidant properties of protein hydrolysates could be useful in many applications of the food industry.     

Comparison of depth- and mass-based approaches for estimating changes in forest soil carbon stocks: A case study in young plantations and secondary forests in West Java, Indonesia

Soil carbon (C) stocks in forest ecosystems have been widely estimated to a fixed soil depth (i.e., 0-30 cm) to clarify temporal changes in the C pool. However, surface elevations change as a result of compaction or expansion of the soil under forest management and land use. On the other hand, the calculation of soil C stocks based on “equivalent soil mass” is not affected by compaction or expansion of forest soil. To contribute to the development of a forest C accounting methodology, we compared changes in soil C stocks over 4 years between depth- and mass-based approaches using original soil data collected at 0-30 cm depths in young plantations and secondary forests in West Java, Indonesia. Our methodology expanded on the mass-based approach; rather than using one representative value for the mass-based calculation of soil C stocks, we adjusted individual values, maintaining the coefficient of variance in soil mass. We also considered the effect of an increase or decrease in soil organic matter on equivalent soil mass. Both increasing and decreasing trends in soil C stocks became clearer when the mass-based approach was used rather than the depth-based approach. The trends in soil C stocks based on equivalent soil mass were particularly evident in the surface soil layers (0-5 cm) and in plantation sites, compared with those for soil profiles including subsurface soil layers (0-30 cm) and in secondary forests. These trends in soil C stocks corresponded with temporal trends in litter stocks. We suggest that equivalent mass-basis soil C stock for the upper 30 cm of soil be calculated based on multiple soil layers to reduce estimation errors. Changes in soil organic matter mass had little effect on the estimation of soil C stock on an equivalent mass basis. For the development of a forest C accounting system, the mass-based approach should be used to characterize temporal trends in soil C stocks and to improve C cycle models, rather than simpler methods of calculating soil C stocks. These improvements will help to increase the tier level of country-specific forest C accounting systems.     

A study of the effects of trampling on the vegetation of Lake Huron sand dunes at Pinery Provincial Park

Plots in established heath-grassland vegetation and pure stands of Calamovilfa longifolia (Hook) Scribn. on Lake Huron sand dunes were subjected to tramppling treatments at various intensities during 1977 and 1978 and were monitored for one year following treatment. Both heath-grassland and Calamovilfa plots given 50 walking passages showed complete recovery within one year after treatment. Heavier treatments (200 walking passages) on Calamovilfa caused a significant reduction in cover one year later. Heavily trampled heath-grassland plots, although visually similar to their controls, had a continued loss of lichen cover over one year. Several species including Arctostaphylos uva-ursi (L.) Spreng., Andropogon scoparius Michx., some Carex species, Liatris cylindracea Michx. and Rosa blanda Ait. initiated new growth in the fall following heavy trampling treatment, but only shoots of Arctostaphylos survived the winter.     

Pesticide and Heavy Metals Residue in Wastewater, Soil and Plants in Wastewater Disposal Site Near Al-Lajoun Valley, Karak / Jordan

Disposal of raw wastewater and sludge creates thepotential for pesticides and heavy metal contamination. Afield study was conducted to determine the residueconcentration level of chlorinated pesticides and four heavymetals (Zn, Pb, Cu and Ni) in raw wastewater, soils andplants at Karak raw wastewater disposal site. The resultsindicated that the investigated area was heavily contaminatedwith various types of pesticides. The distribution of different pesticides in soils and wastewater was influencedby the solubility of these pesticides such that the higherthe solubility the more is present in water phase and viceversa. Vinclozoline was the dominant pesticide in most of thesamples. Some pesticides of which application is restrictedto be used in Jordan, such as DDT and its metabolites, weredetected in the investigated area.Heavy metals existed in relatively higher concentrationsin soils than in wastewater, which was due to the high pH ofthe wastewater enhancing its precipitation. Zinc was thehighest among the analyzed heavy metals in both wastewaterand soils.The residue level of both heavy metals and chlorinatedpesticides were highest at the emission source decreasinggradually with distance.     

托木尔峰自然保护区地衣的补充研究

我们根据多年的研究并结合前人的工作进一步地整理了分布在新疆托木尔峰自然保护区的地衣种类。分析该地区的地衣种有１２０个，分别隶性于４９属，其中有１１个变种和４个变型。调查中我们还发现该地区地衣随着海拔高度的升高而有所不同，北坡和南坡也有明显的差异。     

Mango seed kernels as an energy source for chicks1

1. Chemical analysis of a sample of ground mango seed kernels (MSK) revealed the following percentage composition: dry matter, 91.55; ash, 1.97; protein, 6.74; ether extract, 12.53; fibre, 1.30; nitrogen‐free extract, 77.46.

2. The ME content of MSK was 1.82 kcal/g.

3. The percentage retention of the crude fat content of MSK was only 3.38%.

4. Substituting MSK for corn at 10 or 20% led to reduced growth rate and poorer food consumption and a reduced efficiency of food utilisation in the period 0 to 4 weeks.     

近50年来塔里木盆地南、北缘干湿状况变化趋势分析

全球变暖大背景下,塔里木盆地边缘绿洲气候变化趋势研究已成为研究的热点。文中利用塔里木盆地南、北缘17个典型绿洲气象站1959-2008年的气象资料,使用联合国粮农组织(FAO)推荐的Penman-Monteith公式,计算近50年潜在蒸散量,定义了地表干燥度指数。在此基础上,对塔里木盆地南、北缘,近50年气候变化特征及其成因进行对比分析。结果表明:塔里木盆地南、北缘气候变化与全球气候变化趋势基本一致,但又具有明显的区域性特点:塔里木盆地南、北缘潜在蒸散量均在波动中呈减少趋势,南缘递减速度比北缘快;干燥度指数也均在波动中呈缓慢减小趋势,其中南缘干燥度指数递减速度比北缘快;总之塔里木盆地南、北缘绿洲有缓慢向暖湿转化的迹象,这对气候极端干燥的塔里木盆地边缘绿洲生态环境的改善和农业生产有积极的影响。     

Wheat Seed Presoaking for Improved Germination

Seed presoaking improves wheat germination under marginal moisture conditions. The duration of seed presoaking was studied at The University of Arid Agriculture, Rawalpindi, using 10 wheat varieties. Seed presoaking beyond 12 h does not improve germination further, and beyond 21 h, germination rate is drastically reduced.