A New Method for Finding Small Vertebrate Fossils: Ultraviolet Light At Night

Vertebrate fossils from many different formations fluoresce when exposed to ultraviolet (UV) light. In this paper field observations and controlled experiments in the Chadron Formation (White River Group, late Eocene) of Wyoming are used to assess the utility of searching for fossils at night using ultraviolet light. The results indicate that, especially for very small teeth and egg-shell fragments, searching with ultraviolet light at night can result in significantly more specimens than searching during daylight hours. This method has the potential to increase sample sizes for small vertebrate specimens that are often overlooked when using standard collecting techniques.     

The use of arbuscular mycorrhizae to control onion white rot (Sclerotium cepivorum Berk.) under field conditions

 A field experiment was carried out to determine the effects of the inoculation of onion (Allium cepa L.) with Glomus sp. Zac-19 on the development of onion white rot (Sclerotium cepivorum Berk.) and on onion production. Mycorrhization delayed onion white rot epidemics by 2 weeks and provided a significant protection against the disease for 11 weeks after onion transplanting, as compared with nonmycorrhizal controls. Mycorrhizal plants showed an increase of 22% in yield, regardless of the presence of the white rot pathogen. Accepted: 8 January 1996     

Use of seedling progeny tests for genetical studies as part of a potato (Solanum tuberosum subsp. tuberosum) breeding programme

A diallel set of crosses, including selfs and some reciprocal crosses, was made between 15 parents chosen for their male fertility from those included in a tetraploid potato (Solanum tuberosum subsp. tuberosum) breeding programme at the Scottish Crop Research Institute. Seedling progeny tests were used to evaluate the progenies for non-race-specific resistance to late blight (Phytophthora infestans) in both foliage and tubers, quantitative resistance to the white potato cystnematode (PCN) (Globodera pallida) and the commercial worth of their tubers as judged by breeders' visual preference. No reciprocal differences were found. Comparisons of the selfs and crosses revealed inbreeding depression for breeders' preference, which varied among the parents from negligible to severe, whilst there were also statistically significant differences for foliage and tuber blight, but not for PCN. When the selfs were omitted from the combining ability analyses, large differences in general combining ability (GCA) were found for all four traits, and smaller differences in specific combining ability for tuber blight and breeders' preference. The only statistically significant correlation between GCAs for different traits was a favourable one of r = 0.56 between foliage and tuber resistance to late blight. It was concluded that prospects were good for simultaneously improving all four traits by multitrait genotypic recurrent selection.     

Pseudomonocystis sp., an Eugregarine Protozoan Pathogen of the Coconut Root Grub, Leucopholis coneophora

Populations of the coconut root grub , Leucopholis coneophora, were infected by an eugre garine protozoan pathogen , Pseudomonocystis sp . The pathogen infected 22.7% third - instar L. coneophora larvae in the field . The infected larvae produced 1 - 84 (average 37 . 11) milky - white , membranous , elliptical cysts measuring 2 . 64 1 . 24 mm . Each cyst contained about 3 . 80 105 mucilaginous spores . The spores were elliptical with two tubular polar caps , thick - walled , ornamented with irregular ridges and furrows , and measured 26 . 04 13 . 61 mum . The LD and LT for oral inoculation of spores into third - instar larvae were 9 . 86 104 50 50 spores / larva and 27 . 62 days respectively . Ingestion of spores with or without food and connibalism of infected larvae were the modes of transmission of the pathogen .     

笼养白头叶猴夏季水分摄入与消耗的初步研究

叶片中的水分含量是白头叶猴水分的主要来源,占水分需求总量的８３．６８％,其它的１６．３２％来自于自由水。在笼养条件下,白头叶猴可饮用自来水,野生状态下,动物饮用露水或雨水。尽管饮水行为不是每天都有,但能经常观察到,特别是在夏季雨后．除了体表和呼吸系统的水分蒸发外,白头叶猴通过尿和粪便丢失的水分含量分别是４４．６８％和５５．３２％。     

Ontogeny of calbindin-D28K and calretinin in developing chick kidney

The ontogeny of two calcium-binding proteins (calbindin-D_28k and calretinin) was studied by immunohistochemical techniques in developing chick kidney. This study showed the presence of calbindin on the 5th incubation day and calretinin on the 7th incubation day in mesonephric distal and connecting tubules, and in the medial wall of the Wolffian duct. At later stages, immunostaining for these two proteins, in particular for calretinin, was also demonstrated in some metanephric proximal tubules. Glomeruli and Bowman's capsules were negative both in the mesonephros and metanephros. The presence of calretinin in the developing kidney has thus been demonstrated for the first time. The early expression of calbindin and calretinin in mesonephric distal tubules suggests their role in regulating the final excretion of calcium. The different patterns of immunoreactivity of the walls of the Wolffian duct can be correlated with their different histogenetic and histological features.     

茶园冬季乔木落叶的分解和矿质元素释放

在我国南方存在着一种传统植茶方式——茶林复合生态系统,近年来人们已逐步认识到它在维持土壤肥力,抗御自然灾害和保证茶叶内质特性等方面的作用,然而对冬季乔木落叶分解和矿质元素释放的作用尚无报道。本文是对安徽省黄山市休宁县茶树-乌桕复合园和茶树-板栗复合园的冬季乔木落叶分解的研究,为全面认识茶林复合生态系统的性质提供依据。     

松茶间作茶树叶片的解剖构造和气孔活动

本文利用光镜技术和MK-3型自动气孔计对松茶间作和单作茶园茶树叶片的解剖构造和气孔传导力进行了比较研究。研究表明,间作茶园茶树叶片的上表皮、栅拦组织和全叶均比单作茶树薄,分别为单作茶树的82.7％,78.2％和67.2％,叶质柔嫩。叶片气孔传导力比单作茶园低。嫩叶传导力>老叶;1芽5叶新梢按叶序3叶>2、4叶>1、5叶;按树冠垂直分布,冠上叶(0—5cm)>冠中叶(10—15cm)>冠下叶(30cm左右)。说明气孔传导力不仅受生态条件影响,与自身的叶龄、叶位等生理机能也有密切关系。     

拟除虫菊酯类农药对茶树害虫的生物活性与残留降解

本文报道了溴氰菊酯、联苯菊酯、氯氰菊酯、顺式氯氰菊酯、杀灭菊酯、功夫菊酯和二氯苯醚菊酯等七种拟除虫菊酯类农药对茶树主要害虫的杀虫效果和在茶树叶片上的降解动态试验结果.上述七种拟除虫菊酯类农药对鳞翅目茶树害虫的幼虫都具有极高的毒力,但对其他害虫的活性谱则表现有差异.它们在茶树芽梢上的降解速率常数为0.20—0.28天^-1,在茶树上的半衰期为2.5—3.5天,明显较有机磷农药稳定.在影响降解的因素中,挥发、热分解、雨水淋洗的作用不大,由茶梢生长稀释所起的作用较为明显.鲜叶中的农药残留在加工过程中的降解率为15—45%,平均20%,远低于有机磷农药.成茶中的残留农药在泡茶过程中由于他们的低水溶性,因此浸出率很低,一般仅有1—4.5%.     

Effect of temperature on isotonic twitch of white muscle and predicted maximum swimming speeds of skipjack tuna,Katsuwonus pelamis

Synopsis Latent period, rise time, contraction time, and half relaxation time from isotonic contractions of isolated white muscle samples from skipjack tuna, Katsuwonus pelamis, were determined at 20°, 27°, and 34° C. These parameters were found to be inversely proportional to temperature (Q₁₀ = 1.47, 1.67, 1.62, and 1.72, respectively). The data show that contraction time and the effect of temperature on contraction time of skipjack tuna white muscle are not unique when compared to other equal-sized teleosts. Based on contraction time, maximum swimming speeds at each muscle temperature were calculated and found not significantly to exceed the maximum speeds of other equal-sized teleosts, when comparisons are made at the same white muscle temperatures