不同浓度MNP与水稻种子萌发和幼苗生长间的相关性研究

MNP（2-methoxy-5-nitro-phenal的钠盐)是一种植物生长调节剂,它是笔者参照类似物的合成原理和方法研制而成。本文研究了MNP对水稻种子萌发和幼苗生长的作用,从而为合成物MNP在农业上的应用。提供了科学依据。     

GROWTH AND METABOLISM OF THE EMBRYO AND ATTACHED SEEDLING OF THE VIVIPAROUS MANGROVE,RHIZOPHORA MANGLE

Fruits of Rhizophora mangle were collected at various stages of development, separated into fruit wall, testa, and embryo or seedling. Wet weight, dry weight, and percent water content was determined for each. All parts of the fruit showed a similar growth pattern with a period of rapid exponential growth during the first 100 days, followed by a period of slower growth after the radicle-hypocotyl axis emerged through the fruit wall. In the final 45 days of seedling attachment the fruit wall and testa did not grow, and seedling growth rate was further reduced. Water content of the fruit wall was constant at 65 % throughout development; that of the testa decreased uniformly from 60 to 54%; embryo water content was uniformly 80%. In the germinated seedling, water content declined progressively to 58 % by the time detachment occurred. Growth of isolated seedlings in sterile culture was not responsive to inhibition by abscisic acid or to stimulation by benzyl adenine, and these hormones had no effect on incorporation of ³H-amino acids into protein or of ³H-uridine into RNA. These results are interpreted in relation to a theory which proposes that development of water stress in the seed is the signal for the inception of dormancy.     

USE OF GROWTH CHARACTERISTICS IN STUDIES OF MORPHOLOGIC RELATIONS. I. SIMILARITIES BETWEEN EPIBLAST AND COLEORHIZA

Foard , Donald E., and Alan H. Haber . (Oak Ridge Natl. Lab., Oak Ridge, Tenn.) Use of growth characteristics in studies of morphologic relations. I. Similarities between epiblast and coleorhiza. Amer. Jour. Bot. 49(5): 520–523. Illus. 1962.—We compared the characteristics of wheat epiblast, coleorhiza, and leaves during germination and seedling growth. Although the epiblast and coleorhiza grow without cell division during germination, they sometimes produce hairs that resemble root hairs but are different in form and mode of origin from leaf hairs. Despite the similar orientation of the epiblast and leaves with respect to the main axis of the plant, during growth the epiblast changes shape such that the axis of greater linear extension per millimeter is perpendicular to the main axis of the plant, whereas leaves change shape such that the greater rate of linear extension per millimeter is parallel to the main axis of the plant. Indoleacetic acid treatment produces excessive and disorganized growth of both the epiblast and coleorhiza but retards leaf growth. Gibberellic acid stimulates, whereas (2-chloroethyl)trimethylammonium chloride retards leaf growth. Neither substance significantly affects epiblast or coleorhiza. We conclude that the epiblast is not leaf-like, but together with the coleorhiza forms a single, continuous structure. This paper illustrates how a wide variety of growth characteristics may be used to complement classical anatomic approaches in studies of morphologic relations.     

THE RELATIONSHIP BETWEEN THE PROMOTION OF ELONGATION OF FERN PROTONEMATA BY LIGHT AND GROWTH SUBSTANCES

Germinating spores of the fern Onoclea sensibilis L. were grown in darkness, so that they developed as filaments (protonemata). Brief daily exposure of the filaments to red, far-red or blue light increased the rate of filament elongation. Filament elongation was also promoted by indoleacetic acid. When filament elongation was promoted with both indoleacetic acid and exposure to light, the growth promotions caused by red and far-red light were additive to auxin-induced growth. Blue light promoted elongation only at sub-optimal concentrations of auxin. Elongation induced by guanine was additive to red- and far-red-induced elongation. Gibberellic acid had no effect on elongation under any condition. Blue-light-induced elongation resembled auxin-induced elongation in its requirement for exogenous sucrose and sensitivity to inhibition by parachlorophenoxyisobutyric acid. Red and far-red light were active regardless of the presence or absence of sucrose and promoted elongation at a concentration of parachlorophenoxyisobutyric acid which completely inhibited blue-light-induced elongation.     

QUANTITATIVE STUDIES OF THE GROWTH OF MOUSE EMBRYO CELLS IN CULTURE AND THEIR DEVELOPMENT INTO ESTABLISHED LINES

Disaggregated mouse embryo cells, grown in monolayers, underwent a progressive decline in growth rate upon successive transfer, the rapidity of the decline depending, among other things, on the inoculation density. Nevertheless, nearly all cultures developed into established lines within 3 months of culture. The first sign of the emergence of an established line was the ability of the cells to maintain a constant or rising potential growth rate. This occurred while the cultures were morphologically unchanged. The growth rate continued to increase until it equaled or exceeded that of the original culture. The early established cells showed an increasing metabolic autonomy, as indicated by decreasing dependence on cell-to-cell feeding. It is suggested that the process of establishment involves an alteration in cell permeability properties. Chromosome studies indicated that the cells responsible for the upturn in growth rate were diploid, but later the population shifted to the tetraploid range, often very rapidly. Still later, marker chromosomes appeared. Different lines acquired different properties, depending on the culture conditions employed; one line developed which is extremely sensitive to contact inhibition.     

E1A激活基因阻遏子表达与小鼠胚胎血管发生的关系

目的探讨E1A激活基因阻遏子(CREG)蛋白表达与小鼠动脉形态学发生的关系,了解CREG蛋白在血管发育中的生物学作用。方法制备E9.5d-E18.5d胎鼠、新生1d、28d和2月成鼠不同脏器功能血管的石蜡组织切片,观察主动脉发生过程中的形态学变化;采用免疫组化染色法观察不同发育时相的血管细胞中CREG蛋白和血管平滑肌细胞(vascular smooth muscle cells,VSMCs)标记物肌动蛋白(SMα-actin)的表达变化。结果HE染色显示E9.5d的胚胎血管由单层血管内皮细胞构成,免疫组化显示CREG表达阳性,主要定位于血管壁的单层内皮细胞中,SMα-actin表达为阴性;E10.5d的胚胎血管内皮细胞周围开始出现少量SMα-actin表达阳性的原始VSMCs,同时CREG蛋白表达,定位与SMα-ac-tin蛋白一致。自E12.5d开始SMα-actin蛋白在血管中膜VSMCs中表达增强并持续至成年。CREG蛋白在三层结构的血管细胞中均为阳性表达,其表达强度在E15.5d达到最高,E18.5d表达下降并维持至成年。进一步分析CREG蛋白在成年鼠心、肺、脾和肾等多个脏器血管中的分布,发现所有脏器血管细胞均表达CREG,但表达丰度明显不同,在储存血管和分配血管中CREG蛋白呈高表达,在调节血管中低表达。结论CREG蛋白在小鼠胚胎血管发育早期、持续表达的特点及其在不同脏器功能血管中表达的差异,提示CREG蛋白可能通过调控并维持血管细胞,特别是VSMCs的分化,参与了胚胎血管发生的调控。     

噬菌体颗粒大小与其遗传控制的噬菌斑大小的关系

测定培养温度、琼脂浓度、感染系数、培养基丰度和时间等因子对形成噬菌斑大小的影响程度,从而排除了影响噬菌斑大小的非遗传本底。分析电镜下噬菌体颗粒大小和平板上噬菌斑大小两者之间的关系,发现在同一容量较恒定的细胞内,不向噬菌体其生物合成总量趋于相等,该原理解释了决定噬菌斑大小的主要遗传控制方式。计算并推导出在一定程度上可反映噬菌体颗粒大小的经验公式。     

GROWTH STUDIES OF THE ROOT OF INCENSE CEDAR,LIBOCEDRUS DECURRENS. I. THE ORIGIN AND DEVELOPMENT OF PRIMARY TISSUES

Wilcox , Hugh . (State U. Coll. of Forestry, Syracuse, New York.) Growth studies of the root of incense cedar, Libocedrus decurrens. I. The origin and development of primary tissues. Amer. Jour. Bot. 49(3): 221–236. Illus. 1962.—The anatomical features of active and dormant roots of incense-cedar seedlings are described and discussed in relation to various problems of differentiation and morphogenesis. Autoradiographs confirm the presence of a group of relatively inactive cells at the site of the apical initials. During periods of maximum growth activity, the presence of a quiescent center is accentuated by a peak in number of divisions in adjacent tissues. With diminution in growth activity, the peak occurs closer to the quiescent center and the size of the meristem appears to diminish. During dormancy, the configuration of the initial region seems to indicate the existence of apical initial cells which coincide with a minimal constructional center, as determined by studies of cell lineage. Roots whose apical cells retain their meristematic appearance are able to resume growth after a period of dormancy, whereas roots whose apical cells undergo vacuolation are likely to perish. Graphs are presented to show the functional relationships between growth rate and the varying distances from the apical meristem at which the tissues of the root differentiate and mature. Although early differentiation of precursory phloem could be discerned almost as soon as early vacuolation of metaxylem, its recognition was more dependent upon subjective judgment. The functional relationship between differentiation and growth rate was most pronounced in the maturation of protoxylem elements, the development of Casparian strips in the endodermis, the development of suberin lamellae in the endodermis, and by the development of phi layers in the inner cortex.