二月兰形态性状的变异分析

二月兰(Orychophragmus violaceus)是集食用、保健、饲用和观赏于一身的优良地被植物。其遗传背景单一、生长周期短,是发展模式植物的优良材料。为了开发其育种价值,我们对二月兰的形态变异式样进行了初步分析。共选取了北京和南京地区的7个居群的34个表型性状进行观测。通过计算分析发现:株高、茎和花序分枝等性状受环境影响较大,因而其分类价值不大;叶形、毛被、叶缘锯齿等性状的变异在居群内是连续的,所以也不是可靠的分类性状;而花部性状的一些变异,包括花瓣的颜色、大小、形态,基本不受环境影响,且这些变异在居群内是不连续的,所以其分类价值相对较高。对17个数值性状的方差分析和多重比较结果表明,在同一年度内,大部分性状在不同地区间差异不显著,在居群间差异极显著;而在不同年度内,居群间差异不显著。最后,对7个居群和30个表型性状进行了数量分类:Q分析表明北京颐和园、南京紫金山山顶公园和南京中山植物园居群比较相似,而北京圆明园、北京海淀区后八家苗圃、南京情侣园和北京天坛公园居群较相似。R分析揭示了二月兰花部、叶部、反映植株毛被和颜色以及表现植株生长量的性状间均具有一定的相关性。这些研究可为种下等级的划分和进一步的遗传研究以及品种培育提供一定的参数资料。     

基于遗传算法的谷氨酸发酵动力学参数估计

把遗传算法应用于求解谷氨酸分批发酵动力学模型参数,取交叉概率Pc=0．8、变异概率Pm=0．06、初始种群为20、遗传世代数为200代,能进一步提高谷氨酸分批发酵过程状态变量的计算值与实验值的吻合程度。模拟值与实验值对比显示,该动力学模型能很好地反映谷氨酸分批发酵过程。     

Does mother really know best? Oviposition preference reduces reproductive performance in the generalist parasitoid Aphidius ervi

The reproductive success of female parasitoids is dependent on their ability to accurately assess the suitability of a host for larval development. For generalist parasitoids, which utilize a broad range of species and instars as hosts, a set of assessment criteria determines whether a host is accepted or rejected. The suitability of a host, however, can only be imperfectly assessed by the female parasitoid, which can result in the selection of lesser quality hosts for oviposition. In this study we explored the disparity between host quality and host preference using the generalist koinobiotic parasitoid Aphidius ervi Haliday (Hymenoptera: Aphidiidae) and the host Aulacorthum solani (Harris) (Homoptera: Aphididae), the foxglove aphid. The second instar hosts produced the highest level of reproductive success, while third and fourth instars resulted in a substantially reduced reproductive performance. When given a choice of host instars, parasitoids preferred the older hosts for oviposition disregarding their reduced suitability for larval development. Results are discussed in context of mechanisms involved in A. ervi host selection and biases in the criteria used to assess hosts that may arise when parasitoids transfer host species between generations.     

OBSERVER VARIABILITY IN PINNIPED COUNTS: GROUND-BASED ENUMERATION OF WALRUSES AT HAUL-OUT SITES

Pinnipeds are often monitored by counting individuals at haul-out sites, but the often large numbers of densely packed individuals at these sites are difficult to enumerate accurately. Errors in enumeration can induce bias and reduce precision in estimates of population size and trend. We used data from paired observers monitoring walrus haul-outs in Bristol Bay, Alaska, to quantify observer variability and assess its relative importance. The probability of a pair of observers making identical counts was < 0.1 for walrus groups with >50 individuals. Mean count differences ranged up to 25% for the largest counts, depending on beach and observers. In at least some cases, there was a clear tendency for counts of one observer to be consistently greater than counts of the other observer in a pair, indicating that counts of at least one of the observers were biased. These results suggest that efforts to improve accuracy of counts will be worthwhile. However, we also found that variation among observers was relatively small compared to variation among visits to a beach so that efforts to account for other sources of variation will be more important.     

hp‐rare 1.0: a computer program for performing rarefaction on measures of allelic richness

The number of alleles in a sample (allelic richness) is a fundamental measure of genetic diversity. However, this diversity measure has been difficult to use because large samples are expected to contain more alleles than small samples. The statistical technique of rarefaction compensates for this sampling disparity. Here I introduce a computer program that performs rarefaction on private alleles and hierarchical sampling designs.     

On-line estimation of cell growth from agitation speed in DO-stat culture of a filamentous microorganism,Agaricus blazei

A simple, but effective on-line method for estimating the mycelial cell mass concentration from agitation speed data, a most readily-available process variable, has been developed for DO-stat cultures ofAgaricus blazei. The dynamic change of dissolved oxygen concentration (DOC) in the initial transient period and the change in yield were considered in the development of the estimation algorithm or estimator. Parameters in the estimation algorithm were calculated from the agitation speed data at 20% of DOC. The proposed estimator could accurately predict the cell mass concentration regardless of DOC levels in the tested range of 10–40%, showing a good extrapolation capability.     

Estimating abundance and spatial distribution patterns of the bubble crab Dotilla fenestrata (Crustacea: Brachyura)

Abstract The bubble crab Dotilla fenestrata forms very dense populations on the sand flats of the eastern coast of Inhaca Island, Mozambique, making it an interesting biological model to examine spatial distribution patterns and test the relative efficiency of common sampling methods. Due to its apparent ecological importance within the sandy intertidal community, understanding the factors ruling the dynamics of Dotilla populations is also a key issue. In this study, different techniques of estimating crab density are described, and the trends of spatial distribution of the different population categories are shown. The studied populations are arranged in discrete patches located at the well‐drained crests of nearly parallel mega sand ripples. For a given sample size, there was an obvious gain in precision by using a stratified random sampling technique, considering discrete patches as strata, compared to the simple random design. Density average and variance differed considerably among patches since juveniles and ovigerous females were found clumped, with higher densities at the lower and upper shore levels, respectively. Burrow counting was found to be an adequate method for large‐scale sampling, although consistently underestimating actual crab density by nearly half. Regression analyses suggested that crabs smaller than 2.9 mm carapace width tend to be undetected in visual burrow counts. A visual survey of sampling plots over several patches of a large Dotilla population showed that crab density varied in an interesting oscillating pattern, apparently following the topography of the sand flat. Patches extending to the lower shore contained higher densities than those mostly covering the higher shore. Within‐patch density variability also pointed to the same trend, but the density increment towards the lowest shore level varied greatly among the patches compared.     

新选育饲草玉米品系饲用营养价值初步研究

对利用一年生大刍草和四倍体多年生大刍草分别与玉米杂交选育出的一年生饲草玉米(SC1)和多年生饲草玉米(SC3)生物产量和饲用营养成分进行分析,结果表明:SC1和SC3鲜草年产量分别达115 620kg/hm2、174 045kg/hm2,是普通玉米的4～6倍;SC3的粗蛋白质(CP)和无氮浸出物(NFE)含量最高,分别为17.57%、48.73%,粗纤维(CF)含量最低,为21.65%,其粗脂肪(EE)和灰分(CA)含量分别为4.30%和7.75%;SC1的营养成分含量分别为:(CP)14.73%、(CF)26.09%、(NFE)45.29%、(EE)4.78%和(CA)9.11%;化学营养类型分析表明SC1与SC3分别属NC型和N型,都是高产高饲用价值的新型饲草.     

硫磺菌原变种液体培养代谢物生物活性分析

硫磺菌原变种Laetiporus sulphureusvar.sulphureus在液体培养条件下对果蝇具有致死效应,研究发现在液体培养过程中分泌到细胞外的代谢产物是致死效应的主要原因,并且上清液对果蝇的生物活性受pH值的影响。离子交换树脂柱和高效液相色谱分离分析表明草酸存在于硫磺菌原变种培养液的上清液中并且是果蝇致死效应和培养体系pH下降的一个重要因素。硫磺菌原变种在气升式反应器ALR/ff培养体系中草酸的浓度、菌丝体量和pH值呈简单相关。进一步分析发现还有另外一种结构未知、在碱性条件下呈紫红色的色素也具有致死效应。     

Sensory evaluation of fruit quality and nutritional composition of 20 breadfruit (Artocarpus, Moraceae) cultivars

Twenty breadfruit cultivars growing in afield genebank at Kahanu Garden, National Tropical Botanical Garden, Hana, Maui, Hawaii, were evaluated for sensory attributes and nutrient composition. A taste panel scored eight flavor/aroma attributes, five textural attributes, and color. There were significant differences (P ≤ 0.01) in aroma, visual texture, flavor intensity, sweetness, starchiness, moistness, stringiness, firmness, and color. The greatest differences were in color and texture. Nutrient analyses showed significant differences (P ≤ 0.05) for energy, carbohydrates, ash, crude protein, potassium, magnesium, sodium, iron, copper, and zinc. Considering the versatility of breadfruit as a food, its ease of production, and its nutritional value, the numerous good quality flavorful cultivars available should be more widely grown for sustainable agriculture and food security.