Leaf carbon isotope discrimination,ash content and K relationships with seedcotton yield and lint quality in lines of Gossypium hirsutum L.

In a two-year (2005–2006) study conducted at three sites in central (Larissa) and northern (Alexandroupolis, Thessaloniki) Greece, we aimed to investigate the relationships between seedcotton yield and lint quality with leaf physiological traits (carbon isotope discrimination-Δ, ash content and K concentration). Eighteen lines with their original cultivars (Christina, Flora, Corona) were tested under the ultra-low density of 1.2 plants m⁻². In combined data over years, a significant, positive correlation between seedcotton yield and Δ or ash content was found only in the driest and lowest-yielding site (Larissa), indicating that genotypes that keep their stomata open and in turn exhibit the highest Δ values, had an advantage in such environments. In pooled data from the two most productive sites (Thessaloniki and Alexandroupolis), which had the highest Δ and ash content values, evidenced a negative correlation between seedcotton yield and both physiological traits. Seedcotton yield was negatively related with leaf K concentration in Larissa and Alexandroupolis but no significant relationship was found in Thessaloniki where leaf K concentration was below adequacy limit. Δ was positively related with ash content which suggests that the latter could be a putative surrogate of Δ. Negative correlation between Δ and leaf K concentration was found in two out of three sites (Larissa and Thessaloniki) as well as between ash content and K in one site (Larissa). These findings suggest that K accumulation in leaves is not just a passive procedure via transpiration stream. Significant, linear relationships of each physiological trait between sites showed that genotypic ranking was constant in the three sites, an indication of heritability. Ash content had the highest significance levels and correlation coefficients. Even though significant genotypic differentiation was observed for the three physiological and two of the lint quality traits (i.e. fibre length, micronaire) determined in Alexandroupolis, only a weak, negative relationship between fibre length and leaf K concentration was evident. In sum, leaf physiological traits (Δ, ash content and K concentration) could not be reliably used for yield selection in cotton owing to site-specific effects, which prejudice the yield–physiological traits relationship. Ash content–Δ relationship merits further research in order the former to be established as a putative surrogate of Δ.     

欧石楠扦插技术体系建立及生根动态观察

研究旨在通过对比‘欧石楠’插穗在不同处理下的生根差异,揭示欧石楠插穗的生根规律,从而为进一步完善欧石楠繁殖体系提供理论依据,为其实践生产提供技术支持。在全光照自动喷雾控温大棚内对欧石楠插穗进行不同激素浓度、不同基质、不同插穗类型及不同扦插时期的处理,对插穗的生根率、平均根数、平均根长及生根质量进行LSD及one-way ANOVA分析。欧石楠插穗在1000 mg/L的IBA影响下生根率最高,达到82.43%,且与其他浓度相比差异显著(P<0.05);在椰糠与珍珠岩（椰糠:珍珠岩=3:1）混合基质中,其插穗的各项生根指标均优于其他基质中的插穗;半木质化插穗是最适宜扦插的类型,较其他类型而言,其生根率、平均根数、平均根长达到显著水平(P<0.05),生根质量达到极显著水平(P<0.01);9月份扦插,插穗的生根率可达94.2%。本试验明确了适宜欧石楠插穗生根的激素浓度、基质及插穗类型、扦插时期。     

Do estuaries with different fishing activity have different fish assemblages and populations?

Commercial and recreational fishing have impacts on fish assemblages and populations, but does their combined fishing pressure result in different fish assemblages in estuaries with only one type of fishing activity? This pilot study tested the model that estuaries with only one type of fishing activity have fewer impacts on fish assemblages and populations than estuaries with more than one type because the fishing pressure in the latter will be greater and results in different fish assemblages and taxa. Fish assemblages and populations, including diversity, abundance and size, did not significantly differ despite exposure to different fishing activities. Detecting differences in fish assemblages in estuaries associated with different fishing activities is difficult as smaller scale spatial and temporal factors have a significant influence on the patterns observed. This highlights the importance of paying close attention to the design of sampling programmes. The nested design of this study enabled identification of where greater effort is required to increase the capacity to detect differences. Recommendations for future studies are provided.     

农药“毒死蜱”对家蚕“两广二号”残毒期的统计分析

应用SPSS统计学软件,进行了40％“毒死蜱”农药对“两广二号”家蚕残毒期的曲线拟合分析,及残毒期前后的茧质方差分析。结果表明：“毒死蜱”400mg·L^-1和200mg·L^-1浓度的残毒期分别是24天和19天,在它们之后的蚕茧质量正常。它们的数学模型分别为指数曲线方程：y=170．63690-0．1645x和y=241．1498e^0.2332x。该方法克服了以往农药对家蚕残毒期的确定无数学模型可循,或使用的BASIC编程方法陈旧、繁杂的不足,是一种计算简便、准确和严谨的农药残毒期的分析新方法。     

人为干扰对阿尔泰山林地和草地生态系统健康影响分析

运用生态系统健康综合指数评价模型（VOR）评价阿尔泰山森林和草地生态系统健康整体状况，分析不同人为干扰方式（放牧、旅游和开矿）对阿尔泰山森林和草地生态系统健康影响，并运用单因素方差分析不同人为活动干扰下草地生态系统健康的差异性。结果表明，1）阿勒泰林区林地和草地均处于健康状态；布尔津林区林地处于亚健康状态，草地处于健康状态；富蕴林区林地处于健康状态，草地处于不健康状态。2）受旅游活动影响，布尔津林区旅游样地内区森林处于不健康状态，而草地处于健康状态。阿勒泰林区与布尔津林区旅游样地内草地差异不显著，也处于健康状态。受放牧影响，阿勒泰林区和富蕴林区牧道两侧草地均处于健康状态，但阿勒泰林区的草地组织力、恢复力和活力均高于富蕴林区草地。3）阿勒泰林区旅游样地6-9月草地生物量明显下降，差异十分显著；从牧道两侧草地变化看，6-9月，牧道两侧的草地生物量下降明显，物种丰富度和多样性指数也下降。4）富蕴林区废弃矿区样地外围随着距离增加，草地总生物量出现下降趋势，草总盖度在300 m处增加到最高值。5）3个林区的牧道、旅游和矿区的草地生态系统处于健康状态，除草地组织力指标外，3种人类活动干扰方式下的草地恢复力和活力2个指标影响差异不大。不同人类活动干扰方式下的草地健康水平的排序为牧道>矿区>旅游区，因此更应该注重旅游区草地生态系统的保护和可持续利用。