Resistance to turnip mosaic virus in white cabbage

Summary Resistance in white cabbage to external necrosis caused by turnip mosaic virus had a significant genetic component. Estimates of heritability ranged from 41% to 48%. Resistance to internal necrosis was determined by unknown environmental factors with no significant genetical component. Although correlation between external and internal symptoms was poor in general, plants which had no external symptoms at harvest did not develop internal symptoms during storage. It is proposed that selection for lack of external symptoms will also produce lines resistant to internal symptoms.     

Experimental Study on a Prestressed Frame of Two Spans Under Unsymmetric Load

By the experimental study on a full-dimensioned prestressed frame of two spans, the relative factors are analyzed such as relative height of equivalent compression zone in critical section, secondary moment, ratio of beam rigidity to column and development of cracks in the top of columns etc., which influence the moment distribution of the post-tensioned prestressed concrete frame from the side of internal force redistribution. It is believed that that the factors of relative height of concrete equivalent compression zone and secondary moment influence the moment modulation in most degree, and ratio of column rigidity to beam also plays a part in the moment modulation to some extent. Second, the plastic joints of frame with excessive spans exit in the span which endure the whole load, at last the whole frame is destroyed because of the destruction of the loading frame, the influence to the non-loading span is little.     

实验室内部质量控制方式及结果评价

对使用标准物质或控制样品、使用相同或不同方法进行重复检测,留样再测,使用添加回收率,分析一个物品不同特性结果的相关性等实验室内部质量控制方法及结果评价进行了具体的探讨。为规范实验室内部质量控制方式与结果评价提供参考。     

日粮内添加盐穗木对卡拉库尔羊瘤胃内环境的影响

采用自身对照法试验设计,将9只健康的卡拉库尔公羊分为3组,即对照组、试验组Ⅰ和试验组Ⅱ,研究在日粮中添加盐穗木对卡拉库尔羊瘤胃内环境的影响,结果显示:日粮中添加100 g盐穗木有降低卡拉库尔羊瘤胃液pH值和氨氮(NH3-N)含量的趋势,但盐穗木添加量为200 g时会提高瘤胃液pH值;添加100 g盐穗木可提高瘤胃中菌体蛋白含量,添加量为200 g时会降低菌体蛋白含量;日粮中添加盐穗木对卡拉库尔羊瘤胃液总挥发性脂肪酸(TVFA)含量无影响,有增大乙酸/丙酸比的趋势。     

微生物叶面肥改善龙冈茌梨果实品质的研究

以10 a生龙冈茌梨为材料,研究了不同浓度的微生物叶面肥在其不同发育时期喷施处理对其外观品质和内在品质的影响.结果表明:微生物叶面肥能显著地提高龙冈茌梨的单果重,减小果皮厚度;但是低浓度处理对其果皮色泽和光洁度、果锈数量以及口感的改善效果不明显,只有在高浓度时才稍有改善.微生物叶面肥能显著提高龙冈茌梨果实的可溶性总糖含量以及可溶性固形物含量,能显著地降低龙冈茌梨果实的可滴定酸含量和石细胞含量,但是对果实硬度的改善并不明显.综合不同浓度微生物叶面肥对龙冈茌梨果实外观品质和内在品质的影响,认为较高浓度有助于提高龙冈茌梨的品质,以1∶600处理的效果最好.     

Confirmation of hybrid origin in Arisaema (Araceae) using molecular markers

A population of hybrids between Arisaema triphyllum subsp. stewardsonii and A. dracontium was investigated using molecular markers to document the hybrid origin. Total genomic DNA was extracted from A. triphyllum, A. dracontium, and the hybrids, and subjected to sequence analysis of various regions of intergenic spacer and genes of chloroplast or intergenic spacer and genes of nuclear ribosome for single nucleotide polymorphisms (SNPs). Clustering was performed using the unweighted pair group method with averages (UPGMA) tested by bootstrap (BS). Hybrid origin could not be easily confirmed in some regions. However, dendrograms constructed with a combined sequence analysis of A. triphyllum 26S ribosomal RNA gene [sequence identification (SI) 467] plus A. tortuosum phytochrome C-like (phyC) gene (SI 468) were very similar to dendrograms constructed from sequences of all regions. This suggests that selecting SI 467 and SI 468 would be practical to identify hybrid origins involving two parental species. Clustering of hybrids together with the female parent in most target regions suggests that, in Arisaema, cpDNA is considered maternally inherited.     

火炬松人工林养分体内转移与内循环研究

对江苏省下蜀林场火炬松人工林 (15年生 )地上部分养分体内转移和内循环特点进行了初步研究 ,结果表明 :(1)在体内养分转移中 ,叶的贡献最大 ,N、P、K和Mg元素的平均转移量均大于枝和干 ;地上部分养分N、P、K和Mg元素的转移率分别为 44 9% ,34 5 % ,2 0 8%和 30 7%。 (2 )地上部分养分归还量N、P、K、Ca和Mg元素分别 5 5 787,6 13,2 6 70 ,70 79和 2 0 30kg·hm- 2 ·a- 1 分别占需要量的 36 6 7% ,44 6 5 % 5 5 3% ,78 0 2 %和 42 84% ;地上实际消耗土壤中的养分量N、P、K、Ca和Mg分别为 2 2 48,2 13,4 6 4,2 6 98和 7 41kg·hm- 2 ·a- 1 ,分别占吸收量的 2 3 99% ,2 2 76 % ,11 84% ,2 4 32 %和 2 1 0 9%。 (3)与当地的杉木林和次生栎林相比 ,该火炬松人工林养分利用率高 ,并处于养分消耗阶段。     

永嘉早香柚授粉及保水措施试验

为探索永嘉早香柚的低产原因和降低内裂果措施。进行了授粉和保水措施试验，结果表明，通过授粉能有效提高永嘉早香柚的座果率；授粉配合保水措施能有效降低永嘉早香柚的内裂果和裂瓣率。     

Cost minimization through the use of taungya system in pulpwood plantation establishment

The costs and benefits of the use of three labour alternatives: direct permanent, direct casual and taungya labour in Gmelina arborea pulpwood plantation establishment in Nigeria were investigated. Results show that cost per hectare is lowest with taungya labour and highest with permanent labour with savings in cost of as much as 30% and 47% by taungya labour over casual and permanent labour respectively. The net present value per hectare of investment is highest when taungya labour is used and lowest and negative with permanent labour. Also, the internal rate of return of investment is highest with taungya labour and lowest with permanent labour. The net present values and internal rates of return for Gmelina plantations calculated for the three pulp and paper mills in Nigeria show the same trend in favour of taungya labour.     

内燃机故障声响信号时间序列模型诊断方法

本文运用统计模式识别原理,提出了一种以内燃机声响信号的时间序列自回归系数及自回归倒谱系数作为模式的特征参数,对参考模式和待检模式用灰色系统的关联测度、Mahalanobis距离测度和Kullback-leiber信息量距离测度同时进行识别,并用层次分析法对识别结果进行综合,从而达到诊断故障目的的方法。通过实验验证,表明其是有效而可行的方法。