THE DEVELOPMENT OF THE SENSILIUM OF THREE FLEA SPECIES

Abstract The result of a study on the internal structures during the development of sensilium and anal segment from first instar larva to adult of Leptopsylla segnis (Schinherr 1811), Monopsyllus anisus (Rothschild 1907) and Ctenocephalides felis felis (Bouche 1835) is reported and summarized as follows: (1) The development of the sensilium and anal segment of these fleas is essentially the same. (2) The first sensilium rudiment appears in the early third instar larva on the anterior one-second part of the tergite of the tenth abdominal segment, and in prepupa the eleventh abdominal segment which is composed of the dorsal and ventral anal lobes is formed, and in the pupa the sensilium and its frame are fully developed. (3) The differenced of opinions on the terminal segments of the flea are discussed.     

肥料三要素对六龄参根产量影响的数量分析

本文针对长白山区低肥力白浆土壤,在三因素五水平最优回归设计田间试验的基础上,应用多元统计分析的方法,建立了氮磷钾三种肥料对六龄参根产量影响的肥料效应数学模型。通过对此模型的数学分析,得知氮磷钾三种肥料对六龄参根的产量均有显著影响。其综合增产效应依次为NK＞N＞K＞P,而三种肥料的线性增产效应依次为N＞K＞P。当三种肥料在一定条件下单独使用时,其增产效应依次为N＞K＞P。同时确定了最高产量施肥量和最大利润施肥量,由等产线确定了合理施肥区。     

MORPHOLOGICAL AND HISTOLOGICAL EFFECTS OF TRIFLURALIN ON ROOT DEVELOPMENT

The most obvious external effect of trifluralin on the primary root was an increase in the amount of radial expansion near the root tip. The initial radial expansion of the treated roots occurred in the region of maximum elongation. With increased duration of treatment there was a gradual decrease in the extent of the meristematic tissue zone because of progressive vacuolation and subsequent differentiation. Although trifluralin disrupted the mitotic process, no one type of mitotic figure prevailed. Mitotic activity was not affected in all of the cells, some of which appeared to be undergoing a perfectly normal mitosis. Rates of trifluralin application sufficient to inhibit lateral root emergence without interfering with development of the primary root affected the pericycle and portions of the endodermis. The pericyclic cells were much enlarged in. the regions opposite the protoxylem and had undergone some of the initial phases of lateral root formation. These enlarged pericyclic cells correspond to what have been called primordiomorphs.     

蒽对3种海洋微藻致毒效应的研究

新月菱形藻（Ｎｉｔｚｓｃｈｉａ ｃｌｏｓｔｅｒｉｕｍ）、绿光等鞭金藻８７０１（Ｉｓｏｃｈｒｙｓｉｓ ｇａｌｂａｎａ ８７１０）和亚心形扁藻（Ｐｌａｔｙｍｏｎａｓ ｓｕｂｃｏｒｄｉｆｏｒｍｉｓ）３种海洋微藻用不同深度的蒽胁迫７２ｈ,分别测定３种藻的生长速率、光合色素含量、净光合速率及呼吸速率的变化。结果表明：３种藻对蒽的敏感性由高到低依次为：新月菱形藻、金藻８７０１和亚心形扁藻;３种微呼吸作用受抑制     

THE DISTRIBUTION OF DICTYOSTELID CELLULAR SLIME MOLDS IN SOUTHERN CALIFORNIA WITH TAXONOMIC NOTES ON SELECTED SPECIES

The occurrence and distribution of Dictyostelid cellular slime molds in southern California were investigated by means of a clonal isolation technique that permitted quantitative sampling of populations. Thirteen species were isolated. These include (in approximate order of decreasing frequency): Dictyostelium rosarium Raper and Cavender, D. mucoroides Brefeld, D. sphaerocephalum (Oud.) Sacc. and March., D. aureum Olive, Polysphondylium pallidum Olive, D. minutum Raper, D. giganteum Singh, D. purpureum Olive, P. violaceum Brefeld, D. mucoroides variant, Acytostelium leptosomum Raper and Quinlan, D. polycephalum Raper, and a new species of Dictyostelium. D. rosarium and D. aureum, both rarely reported in the literature, were common and widespread. Trends in habitat preference of the Dictyostelids encountered are discussed. Selected taxonomic details are provided for D. rosarium, D. aureum and members of the “D. mucoroides complex“—D. mucoroides, D. sphaerocephalum, D. giganteum, and a D. mucoroides variant.     

Ca2+对小麦种根及其根毛生长发育的影响

低浓度的ＣａＣｌ２对小麦种根生长、根毛发生和生长无明显影响,高浓度的ＣａＣｌ２（０．１ｍｏｌ／Ｌ）对种根和根毛生长有抑制作用,但不影响根毛的发生。Ｃａ２＋专一性螯合剂ＥＧＴＡ抑制种根生长和根毛的发生及生长,添加一定浓度的外源ＣａＣｌ２,这种抑制作用可被消除。ＣａＭ抑制剂ＴＦＰ（三氟拉嗪）和ＣＰＺ（氯丙嗪）对种根生长、根毛发生和生长均有抑制作用,添加外源ＣａＭ可减弱或消除这种抑制作用。     

DEVELOPMENT AND STRUCTURE OF THE VASCULAR CONNECTION BETWEEN THE PRIMARY AND LATERAL ROOT OF LYCOPERSICON ESCULENTUM

The primary xylem connection between the diarch parent root and the diarch lateral root was derived from the pericycle and stelar parenchyma. Early in lateral root development stelar parenchyma that was positioned between the parent xylem and the primordium divided transversely. These transverse divisions produced a plate of cells, most of which subsequently differentiated into vessel element connectors. After emergence of the lateral root, xylem maturation began in the stelar vessel element connectors and maturation proceeded acropetally into the lateral root. Protoxylem of the lateral root was connected to the metaxylem of the parent root via stelar vessel element connectors. The circular phloem connection was pericyclic in origin. Axial phloem connections which vascularized the lateral root were established with sieve tube elements of both parent phloem poles. Maturation of the phloem connection occurred prior to lateral root emergence. Transaxial phloem, positioned in arches above and below the lateral root vascular cylinder, was derived from the pericycle; and each arch consisted of three to four sieve tube elements. No transfer cells were found in the transaxial phloem.     

WATER STATUS AND THE DISTRIBUTION OF CYANIDIUM CALDARIUM IN SOIL1

The size and photosynthetic ability of Cyanidium caldarium populations in soil were related to the water status of the soil, welter soil, areas having larger populations and more extensive photosynthesis. The application of the direct methods used to the study of other soil algae, mosses, and lichens is discussed.     

SEQUENCE AND PATTERN OF LATERAL ROOT FORMATION IN FIVE SELECTED SPECIES

The proximal-distal distribution of the lateral roots of five species was studied. A detailed investigation was carried out on two of the five species, Ceratopteris thalictroides and Cucurbita maxima. A definite pattern of lateral root arrangement, with a degree of variability related to the number of protoxylem poles, was found in all of the species studied. In the fern Ceratopteris, lateral root initiation was found to be related to the segmentation of the apical cell, which in turn determines the distribution of the laterals. In this species the lateral roots occur in a predictable sequence and they are grouped in pairs. In the angiosperms studied, the pattern of lateral root distribution seemed to depend primarily upon a rather strict longitudinal relationship between the lateral root primordia formed opposite any one protoxylem pole. In Cucurbita maxima, 93.7 ± 5.02% of the lateral root primordia observed were in a specific sequence. The laterals of this species are also arranged in groups. In the other plants studied, Arachis hypogaea, Victoria trickeri, and Eichhornia crassipes, the laterals were not as regularly arranged, but nevertheless they were found to be arranged in groups along the main root axis and not randomly dispersed. Factors controlling the spacing of lateral root primordia include their relationship with the developing vascular system, a direct effect of the parent root apex, and an effect of older lateral root primordia in the same sector of the root.     

SOME EFFECTS OF VIRUS INFECTION ON LEAF WATER CONTENTS OF NICOTIANA SPECIES

Infection with tobacco mosaic virus decreases the water content which detached tobacco leaves attain when kept for 20 hr. in conditions of minimum water stress, and does so more when the plants are kept in light before inoculation than when they are kept in darkness. No such effects of infection during the first day after inoculation were obtained with tobacco leaves infected with either tobacco etch virus or potato virus X , or with Nicotiana glutinosa leaves infected with tobacco mosaic virus. These results, like those showing early effects of TMV on respiration and photosynthesis of tobacco leaves, suggest that inoculation with TMV affects deeper leaf tissues than the epidermis earlier in tobacco leaves than in other leaves, and earlier than other viruses in tobacco leaves.     

侧脑室注射牛磺酸对脑内生长抑素含量的影响

目的和方法：利用放射免疫分析技术,测定侧脑室注射不同浓度牛磺酸后１０ｍｉｎ、３０ｍｉｎ等不同时间内,大鼠部分脑区及血浆生长抑素含量的变化。结果：①侧脑室注射牛磺酸４０ｇ／Ｌ５μｌ１０ｍｉｎ后,垂体、下丘脑及桥延部生长抑素含量明显增加（Ｐ〈０．０５￣０．０１）;３０ｍｉｎ后,垂体、桥延部生长抑素含量恢复正常;②侧脑室注射４００ｇ／Ｌ５μｌ牛磺酸后,下丘脑生长抑系含量较对照组升高（Ｐ〈０．０５￣０．０