不同生态类型小麦品种生长锥分化与温光的关系

本文研究了不同生态类型的七个小麦品种生长锥分化进程及其与温光的关系.结果表明:生长锥分化进程随品种类型而异,春性品种快于冬性品种,但差异最大的是单棱期至二棱初期.伸长期与日平均温度呈极显著的负相关,即温度越高,天数越短.此外,还发现伸长期存在着"积温效应".日照长度是影响单棱期至二棱初期长短的主要因素,所有品种单棱期至二棱初期的天数均与此期的平均日长呈显著的负相关,而冬性品种还与日平均温度呈正相关.高温长日加速二棱初期至雌雄蕊分化进程.     

几个因素对紫肉甘薯食用品质的影响

通过DPS逐步回归分析来研究鲜薯产量、薯块的干物质、花色苷、可溶性糖的含量等因素对紫肉甘薯食用品质的影响.结果表明：薯块干物质含量与食用品质中的水分、质地显著正相关,花色苷含量与食用品质中的水分、质地呈显著负相关,而鲜薯产量和可溶性糖含量与食用品质无显著相关性.质地与影响食用品质的风味、纤维、一般评价等评定指标显著正相关,而水分只与一般评价指标显著正相关.因此,主要通过对质地评定指标的作用,薯块的干物质和花色苷含量是影响紫肉甘薯食用品质的主要因素.     

Potato glycoalkaloids: Increases and variations of ratios in aged slices over prolonged storage

Four commercial cultivars of potatoes were maintained under normal storage conditions at 44 F for 34 weeks. Except for a final 10 week interval tubers were withdrawn at 6 week intervals. After slicing, a portion of the slices was immediately analyzed for total glycoalkaloid content. The remaining slices were aged for four days in the dark at room temperature, then similarly analyzed. The total glycoalkaloid content of the aged slices increased dramatically on aging. This increase on aging of slices reached a maximum early in storage then decreased gradually over the storage period. In determining the individual glycoalkaloids, α-solanine and α-chaconine both increased in these slices, but the greatest increase was in the former. Appearing solely in the aged slices of the Kennebec variety, α-and β-solamarine appeared early in the storage period and gradually decreased over the storage period. Analyses of the unaged slices indicated that the glycoalkaloid content and composition of the potato tubers was little affected by storage. Aging of potato sprouts did not change their glycoalkaloid content.     

Inventory of aspen trees in spruce dominated stands in conserva-tion area

Background: The occurrence of aspen trees increases the conservation value of mature conifer dominated forests.Aspens typically occur as scattered individuals among major tree species, and therefore the inventory of aspens is challenging.Methods: We characterized aspen populations in a boreal nature reserve using diameter distribution, spatial pattern, and forest attributes: volume, number of aspens, number of large aspen stems and basal area median diameter. The data were collected from three separate forest stands in Koli National Park, eastern Finland. At each site, we measured breast height diameter and coordinates of each aspen. The comparison of inventory methods of aspens within the three stands was based on simulations with mapped field data. We mimicked stand level inventory by locating varying numbers of fixed area circular plots both systematically and randomly within the stands. Additionally, we also tested if the use of airborne laser scanning(ALS) data as auxiliary information would improve the accuracy of the stand level inventory by applying the probability proportional to size sampling to assist the selection of field plot locations.Results: The results showed that aspens were always clustered, and the diameter distributions indicated different stand structures in the three investigated forest stands. The reliability of the volume and number of large aspen trees varied from relative root mean square error figures above 50% with fewer sample plots(5–10) to values of25%–50% with 10 or more sample plots. Stand level inventory estimates were also able to detect spatial pattern and the shape of the diameter distribution. In addition, ALS-based auxiliary information could be useful in guiding the inventories, but caution should be used when applying the ALS-supported inventory technique.Conclusions: This study characterized European aspen populations for the purposes of monitoring and management of boreal conservation areas. Our results suggest that if the number of sample plots is adequate,i.e. 10 or more stand level inventory will provide accurate enough forest attributes estimates in conservation areas(minimum accuracy requirement of RMSE% is 20%–50%). Even for the more ecologically valuable attributes, such as diameter distribution, spatial pattern and large aspens, the estimates are acceptable for conservation purposes.     

内陆盐碱的成因及防治对策

地处内蒙高原的河北省内陆河流域；土壤盐碱化使本来就十分脆弱的环境变得更加恶劣，严重制约着当地经济的发展，通过对大清沟内陆河流域的地形、水文地质和土壤水盐的研究，初步论述了内陆盐碱的成因及防治对策，即在上中游建梯田和挖水平工程，节节拦蓄地表径流，减缓水盐向下汇集；下游实行井沟排水、井渠灌溉冲洗、降雨淋洗及生物改良等综合防治和利用措施。     

2004早稻新品种(组合)抗稻瘟病鉴定结果分析

从早稻29个新品种(组合)抗病鉴定结果表明:多为感病或中感病品种,少数为中抗品种,说明近年早稻育种重优质高产,忽视了抗病水平的提高,因而许多品种不能大面积推广;从实用角度对穗颈瘟分级标准提出了疑问,对不利发病气候条件,调节水肥管理提出建议。     

奶山羊产奶性状相关基因的筛选与功能研究进展

奶山羊作为乳用品种的山羊,因其具有奶质优良、产奶性能稳定、乳汁营养丰富等特点,逐渐成为畜牧业发展的一大亮点。经过多年的选种选育,我国现已拥有了多个地方奶山羊品种。随着分子育种技术的发展,对于奶山羊产奶性状相关基因的研究越来越多。对奶山羊产奶性状相关基因的研究进展进行综述,以期为奶山羊优秀基因资源的研究、保护和利用提供理论依据。     

呼中自然保护区阔叶林群落结构及组成特点分析

研究大兴安岭呼中自然保护区阔叶林的群落结构及其组成特点,为大兴安岭绿化造林提供科学理论依据。     

牙鲆人工育苗期间的几种病害与防治

本文报导了1990—1991年大连地区牙鲆(Paralichthys olivaceus)人工育苗期间的几种常见鱼病及防治方法。其中细菌性鱼病2种,寄生纤毛虫病2种,其它鱼病2种。