Fruit abortion in the Chihuahuan-Desert endemic cactus <Emphasis Type="Italic">Opuntia microdasys</Emphasis>

Resource and pollen limitation, as well as pollen/ovule incompatibility, have been proposed as causes to explain fruit abortion. To assess whether abortion in Opuntia microdasys was due to resource and/or pollen limitation and could therefore be reversed fruit set and seed set were studied using controlled pollination experiments on 60 plants that had been randomly assigned a combination of watering and fertilization treatments. On the other hand, to test whether fruit abortion was irreversible, due to pollen/ovule incompatibility, we examined the reproductive biology of the species. This included observations on floral phenology, nectar production, flower visitors, numbers of pollen grains and ovules, and self-pollination experiments. Results showed that O. microdasys is a fully self-incompatible species and its floral biology and the activity of the main pollinator allow constant deposition of incompatible pollen onto stigmas, which may contribute to fruit abortion. Reproductive success was limited by nutrients and pollen, but the fruit set increased only by 58%, compared to 47% of the control, after the experimental addition of pollen, nutrients and water. The magnitude of pollen and resource limitation suggests that similar levels of abortion will be present in good as well as in bad years. Selfing as well as incompatibility between ramets from the same clone and between closely related plants seem plausible candidates to explain the large proportion of fruit abortion, and experimental cross pollination between genotypes identified through molecular markers are necessary to fully understand the considerable abortion rate that remains unexplained after pollen and resource addition. Interestingly, the possible reason why the abortion of energetically expensive fruits has not been eliminated by natural selection is that the aborted fruits are propagules able to root and produce new plants with the same genotype of the mother. Abortion would have a dramatic effect on cross-fertilized genotypes because they result in zero fitness, but it would have a positive effect on the fitness of the maternal genotype because a clonal offspring is produced. Evidently, the exact fitness consequences to the maternal plant will depend on the differences in survival and reproduction of these different offspring types.     

一种复合微生态制剂对养殖水体中生物因子的影响

[目的]研究海水养殖池塘中投放以芽孢杆菌和假单胞菌为主的一种自主研发的微生态制剂对池塘养殖生物、微生物菌相、浮游生物的影响,以期为建立微生物生态调控技术体系提供参考.[方法]实验期间,每隔15d于试验池塘中泼洒微生态制剂一次,每月末取样测量水体和底泥中异养菌和弧菌密度、浮游生物种类和密度,实验结束时测量养殖生物的生长率和成活率.[结果]该微生态制剂能够显著提高南美白对虾和三疣梭子蟹的存活率和生长速度,试验组南美白对虾的存活率和体重增长率较对照组分别提高了11.3％和1 400％,试验组三疣梭子蟹的存活率和体重增长率较对照组分别提高了1.2％和37.5％;微生态制剂能够显著提高海水池塘的异养菌总数,从而抑制致病性弧菌的数量,试验组池水和底泥的异养菌平均密度在整个养殖期较对照组提高了58.5％和51.3％,而试验组水体中致病菌——弧菌的数量在整个养殖期较对照组降低了39.7％;微生态制剂使绿藻门和硅藻门的藻类密度明显增加,对蓝藻和甲藻的生长有抑制作用.[结论]该微生态制剂能够有效地改善养殖池塘中生物群落结构,提高某些养殖品种的生长速度.     

梧宁霉素产生菌诱变选育的研究

以不吸水链霉菌（Ｓｉｒｅｐｔｏｍｙｃｅｓａｈｙｇｒｏｓｅｌｃｎｓ）ＮＳ—２３为出发菌株。菌种斜面孢子萌动后采用紫外线（ＵＶ）、硫酸二乙酯（ＤＥＳ）、秋水仙素及加底物等物理化学因子进行诱变处理,经两代连续处理,从ＵＶ、ＤＥＳ的复合处理中选育出一株产素较高的突变株ＵＤＡ２５７－Ｃ－２４,产素效价比出发菌株提高了２９１．７２％     

Reproductive biology of the Andean-disjunct genusRetanilla (Rhamnaceae)

Various aspects of the reproductive biology of the Andean-disjunct genusRetanilla (DC.) Brongn. were studied in populations ofR. trinervia andR. ephedra located in central Chile and ofR. patagonica in southern Argentina. Flowering extends from -austral- winter (early spring inR. patagonica) to early summer. The small, white, entomophilous flowers are incompletely protandrous and last four to five days. A weak pleasant odor along with nectar and pollen attract thirty-seven diurnal insect species, ten of which are probable pollinators: these include the honey bee, eight species of solitary bees pertaining toAnthophoridae (1 sp.),Colletidae (3 spp.) andHalictidae (4 spp.), and a nemestrinid fly. Although flower morphology and individual flower phenology do not fully prevent self-pollination (and geitonogamy can easily take place), the level of autogamy is low. Therefore, some self-incompatibility mechanism seems operative inRetanilla. Fruit set of open-pollinated flowers is extremely low, with a maximal value of c. 3% inR. patagonica. In this species, ripe fruits contain on average 1.37 viable seeds. Predispersal (maternal) reproductive success (percent ovules becoming viable seeds) is 2.3%. For medium to full-sized individuals this corresponds to c. 4600 potential offspring per year. As presently known,Retanilla is a reproductively uniform group, in which the Andean disjunction seems to have exerted no particular impact, which is consistent with the view that pollination generalization exerts some stabilizing influence on floral morphology and other reproductive traits.Retanilla expresses a basic rhamnacean set of traits (including protandry and self-incompatibility) showing also high pollen production and secondary pollen presentation. The latter two traits seem characteristic of theRetanilla-Trevoa clade, suggesting that a trend to increased male effort and, perhaps, dependence upon polleneating has evolved within the tribe Colletieae.     

The Nutritional Status and Eating Habits of Shift Workers: A Chronobiological Approach

The eating habits of workers may vary according to the season of the year and corresponding work schedule. A study aiming at verifying the changes in their diet in summer and winter, as well as the nutritional status of those who work fixed shifts, was conducted. The distribution during the 24 h in the quantity of calories and macronutrients ingested and the circadian rhythm of calories consumed were also analyzed. The study was conducted on 28 workers subject to three fixed work (morning, afternoon, and night) shifts at a transport company in the city of São Paulo, Brazil. The mean age of the workers was 32.8 (SD ± 5.3) yrs. Their food intake was ascertained by the use of a 3-day dietary record, and their nutritional status was evaluated by their body mass index (BMI), both in winter and summer. Two-way ANOVA (shift and season) showed food consumption—measured in calories/24 h—was significantly higher in winter than summer (F_(1.25) = 11.7; p < 0.001). No statistically significant differences were found among shifts (F_(2.25) = 0.85; p < 0.44), and the interaction effect between shift and season was also not significant (F_(2.25) = 0.15; p < 0.86). No seasonal difference in BMI was detected (Kruskal-Wallis test). Cosinor analyses showed circadian rhythmicity in calories consumed by morning (p < 0.01) as well as afternoon shift workers (p < 0.001), both in the winter and summer. Circadian rhythmicity in calories consumed by night workers was found only in summer (p < 0.01). The changes observed in the workers’ eating habits from one season to another and during the 24 h period show the need for further studies to help develop educational programs to improve the nutrition of shift employees taking into consideration shift schedule and season of the year when work is performed.     

斑翅山鹑巢址选择的研究

１９９１－１９９３年在山西宁武县对斑翅山鹑的巢址选择进行了研究,野外工作中共发现６０个巢,其中绝大多数位于远离林地的农田或灌丝地带,６６．６７％的巢位于向阳的东南坡和西南坡上,对巢址与随机选取的非巢样点所进行的对比分析发现,在１２个栖地参数中,影响巢址选择的５个因素依次为：落叶的数量、地缘宽度、干草的数量、灌丛宽度和梯田高度,判别分析的结果表明,落叶的数量和干草的数量是区别巢址与非巢样点的两个最重     

不同纬度洞巢鸟类对人工巢箱的利用及差异

迄今对洞巢鸟类生活史特征的纬度变异（特别是热带洞巢鸟类的繁殖）了解还十分有限。我们于2018年3至8月,分别在海南吊罗山（热带）、河南董寨（亚热带）和河北塞罕坝（温带）的林缘地带,悬挂相同规格的人工巢箱招引洞巢鸟类繁殖,用以比较不同地理区域的洞巢鸟类对人工巢箱的利用情况及其孵化成效和繁殖成功率。野外共悬挂577个木制巢箱,3个研究地的利用率在海南吊罗山为最低（32.6%）,河南董寨最高（92.0%）。3个地点均有大山雀（Parus cinereus）入住（占总巢数的84.3%）,其孵化成效和繁殖成功率在3个地点不存在显著差异（P > 0.05）。但在河北塞罕坝,大山雀的孵化成效（75.7%）和繁殖成功率（65.7%）显著低于同域繁殖的褐头山雀（Poecile montanus）（97.7% 和97.7%）和煤山雀（Periparus ater）（93.5%和90.3%）（P < 0.05）。研究表明,3个地理区域利用巢箱繁殖的洞巢鸟的种类、数量以及对巢箱的利用率均存在差异,但对于广布种大山雀来说,地理位置的差异并不影响其孵化成效和繁殖成功率。     

Genome-wide patterns of large-size presence/absence variants in sorghum

The presence/absence variants （PAVs） are a major source of genome structural variation and have profound effects on phenotypic and genomic variation in animals and humans. However, little is understood about PAVs in plant genomes. Our previous resequencing effort on three sorghum （Sorghum bicolour L.） genomes, each 12？ coverage, uncovered 5 364 PAVs. Here, we report a detailed characterization of 51 large-size （＆gt;30 kb） PAVs. These PAVs spanned a total size of 2.92 Mb of the sorghum genome containing 202 known and predicted genes, including 38 genes annotated to encode celldeath and stress response genes. The PAVs varied considerably for repeat sequences and mobile elements with DNA trans-posons as the major components. The frequency and distribution of these PAVs differed substantial y across 96＆amp;nbsp;sorghum inbred lines, and the low-and high frequency PAVs differed in their gene categories. This report shed new light on the occurrence and diversity of PAVs in sorghum genomes. Our research exemplifies a new perspective to explore genome structural variation for genetic improvement in plant breeding.     

树鼩驯养繁殖实验动物标准及丙型肝炎动物模型技术平台建设的探讨

目前用于生物医学研究的树鼩大多数来源于野生捕获,由于个体间的差异较大,其实验结果的均匀性和可重复性较差,亟待解决树鼩人工饲养设施条件、繁殖关键技术、动物质量标准等一系列基础科学问题。许多文献报道了树鼩与其他实验动物比较,在肝病研究中具有巨大的开发应用潜力,在丙型肝炎动物模型研究中,亟待解决丙型肝炎病毒(HCV)细胞培养体系、HCV病毒感染剂量与感染途径、HCV病毒对树鼩体外、体内感染后病毒核酸检测、抗体检测和病理检测等技术方法的建立及动物模型评价标准问题。本文就上述问题系统性地进行初步报道,旨在为树鼩早日实现实验动物化和丙型肝炎疾病研究中应用提供科学依据。     

西双版纳茶林及橡胶林区鸟类调查

1983年5—7月,作者对云南省西双版纳的勐海、勐养和勐腊三个地区的茶林和橡胶林区的鸟类区系组成情况进行了调查,其结果若与开发前（郑作新、郑宝赉,1961,1962;A.И.伊万诺夫,1961）的记录对照,在季节时间上有所不同,但该地区的热带雨林和季雨林被开垦种植为茶林、橡胶林及其它经济作物之后,反映出各林区现在的繁殖鸟种类减少很多,鸟类区系组成情况有显著的变化。