Nutritional and hormonal effects on storage proteins in the silkworm,Bombyx mori L.

Starvation of 48 h old fifth instar larvae depressed storage protein titres initially for 48 h but retained the levels comparable to control thereafter, possibly due to nutrients obtained during the 48 h feeding after fourth ecdysis. After an initial decline ligated larvae accumulated maximum storage proteins in haemolymph. This is because of inhibitory juvenile hormone titre at the basal level besides the appropriate release of 20-hydroxyecdysone from the ectopic source(s). Injection of methoprene (10 Μg/larva) repressed accumulation of storage proteins while 20-hydroxyecdysone (10 Μg/larva) increased the same. P-soyatose injection to starved and ligated larvae accelerated storage protein accumulation in haemolymph, signalling nutrient indispensability for initiation of storage protein synthesis at the appropriate time of last instar development inBombyx mori.     

Relations between submarginal and marginal sori in ferns IV. The sori of Osmunda and selected Schizaeaceae and their morphological relations

Developmental types of sori in Osmunda and Schizaeaceae are comparatively studied and discussed in a systematic context. (1) The ``simultaneous marginal sorus' is characterized by a minute knob-like receptacle representing the thickened tip of a short costa, simultaneous initiation of massive sporangia, and absence of indusia. (2) The ``acropetal marginal sorus' is characterized as an accessory outgrowth at the end of a costa or at the margin of a sorophore, comprising a minute or elongated bifacial receptacle, acropetal initiation of massive marginal sporangia, and minute or long-extended or hood-shaped upper indusia. The state of superficial singly-arranged massive sporangia such as in Todea may give rise to the Osmunda type of the simultaneous marginal sorus and to the Schizaeaceae types of the acropetal marginal sorus. Phase differentiation in leaf development combined with complete laminar reduction leads to the Osmunda type, while phase differentiation in leaf lamina development and additional processes may give rise to the Mohria, Anemia, and Lygodium types. These morphological results support recent phylogenetic studies by other authors in disclaiming close relationships between Osmundaceae and Gleicheniaceae, and between Marattiaceae and Ophioglossaceae (``Eusporangiatae'). They also potentially support relationships between Osmunda- ceae and Schizaeaceae or between Ophioglossaceae and Schizaeaceae. The high complexity of the sori in Marattiaceae and Ophioglossaceae is surprising if the two families are viewed as basal groups.     

Studies in Morphogenesis of Brassica oleracea L: I. GROWTH AND DEVELOPMENT OF CABBAGE DURING THE VEGETATIVE PHASE

1. Some characteristics of the growth and development of thecabbage during the. vegetative phase are described and an attemptis made to relate these characteristics to maturation time infive varieties. 2. Cabbages may take 60 days to reach the grand period of growthduring the summer, yet under similar conditions an early varietycain grow to maximal weight in a further 50 days. 3. The cabbage head differs from the well-defined storage organsof the turnip and carrot; the leaf portion, from which the headis comprised, does not grow at a much greater rate than thatof the other primary parts of the plant as does the root portionof turnip and carrot. Nevertheless the head contains reservesugars and therefore presumably functions as a storage organ. 4. Five varieties differed in rate, of leaf initiation, growthin length of stem, and time of flower initiation, but none ofthe differences were correlated with sequence of maturation. 5. The head is the aggregate of folded leaves, and increasesin proportion to the rest of the plant mainly because leavesare initiated and continue to grow in size after leaf unfoldinghas slowed down or ceased. The time of retardation of leaf unfoldingis a varietal characteristic which largely determines the timeof maturation. One possible explanation of the phenomenon ofcessation of leaf unfolding, based on the configuration of youngleaves around the stem apex, is discussed.     

Floral ontogeny in tribe Dalbergieae (Leguminosae: Papilionoideae):Dalbergia brasiliensis, Machaerium villosum s. l.Platymiscium floribundum, andPterocarpus rotundifolius

Floral organogenesis and development of the tropical legume treesDalbergia brasiliensis, Machaerium villosum, Platymiscium floribundum, andPterocarpus rotundifolius were studied using scanning electron microscopy. The aims were to compare ontogenies and to elucidate if floral ontogenetic data will provide new character states diagnostic of the tribe Dalbergieae, which is considered a basal papilionoid tribe and primarily defined on fruit characters. Organ inception is principally acropetal in all taxa studied. Carpel inception is, however, consistently precocious. InD. brasiliensis sepals are initiated in an order not previously reported in Papilionoideae. It may be considered modified helical. InP. rotundifolius the inner whorl of stamens initiate in an unusual way, this is lateral two stamens first, then the two abaxial ones, and last the adaxial one, opposed to the unidirectional order usually seen in Papilionoideae. Generally the differences in flower development among the studied genera appear at initiation and late stage in ontogenesis, rather than at mid-stage.     

Morphogenetic mechanisms of coelom formation in the direct-developing sea urchin <Emphasis Type="Italic">Heliocidaris erythrogramma</Emphasis>

Indirect development via a feeding pluteus larva represents the ancestral mode of sea urchin development. However, some sea urchin species exhibit a derived form of development, called direct development, in which features of the feeding larva are replaced by accelerated development of the adult. A major difference between these two developmental modes is the timing of the formation of the left coelom and initiation of adult development. These processes occur much earlier in developmental and absolute time in direct developers and may be underlain by changes in morphogenetic processes. In this study, we explore whether differences in the cellular mechanisms responsible for the development of the left coelom and adult structures are associated with the change in the timing of their formation in the direct-developing sea urchin Heliocidaris erythrogramma. We present evidence that left coelom formation in H. erythrogramma, which differs in major aspects of coelom formation in indirect developers, is not a result of cell division. Further, we demonstrate that subsequent development of adult structures requires cell division.     

Comparative anatomy and ultrastructure of active and dormant vascular cambium in rhizome ofBotrychium ternatum

Vascular cambium ofBotrychium ternatum rhizome varied according to age, position and season was studied by light and electron microscopy. Cambium at the 6th internode (6-year-old cambium) had the greatest number of active cambial cells in August and September, thus it was in the most active stage. The active cells were characterized by the presence of a large vacuole, few storage materials such as starch grains within plastids or lipid droplets, a thin tangential wall; and various cell organelles in the thin peripheral layer of cytoplasm. When the 6-year-old cambium reached its dormant season after November, the dormant cells were filled with numerous storage materials and had few cell organelles. Our observations suggested that the initiation and cessation of cambial activity may be correlated with the annual life cycle of this plant: the vegetative and reproductive leaves began to emerge in June and July, respectively, and the sporophyll withered in November after the spore dispersal. Most cambial cells at the 10th internode, which remained in a dormant state throughout the year, were filled with numerous storage materials. Our results indicated that the activity of vascular cambium in the 10th internode was determinate.     

Cell division inCarteria crucifera (chlorophyta): The role of the endomembrane system and phycoplast

Summary Phycoplast-mediated cytokinesis in the primitive green algal flagellate,Carteria crucifera, has been examined by electron microscopy. The key developmental foci during cell division are mobile centriole-MTOCs which control mitotic spindle formation, the establishment of the plane of cytokinesis, the initiation of the cytokinetic furrow, the formation of the phycoplast and the formation of morphogenetic microtubular arrays. The cytokinetic cleavage mechanism entails an ingressive furrowing closely associated with a prolific network of internuclear endoplasmic reticulum. Dictyosome activity is limited to the cleavage initiation zone and is responsible for the production of wall precursor-containing vesicles. Dictyosome materials do not contribute directly to the growing furrow edge. Potassium antimonate staining patterns reveal the cytokinetic ER as a storage/control site for calcium during cytokinesis. Discussion of possible models concerning this cytokinetic mechanism is presented.     

蓝堇草属(毛茛科)花形态发生的扫描电子显微镜观察

花的发生和发育过程研究可以发现早期进化的轨迹,为系统发育的研究提供重要线索。蓝堇草属(Leptopyrum)为毛茛科唐松草亚科一单种属,仅包含蓝堇草一种,其花的发生和发育过程仍为空白。为了深入理解唐松草亚科乃至毛茛科花发育多样性和演化规律,该文运用扫描电子显微镜(SEM)观察了蓝堇草各轮花器官的形态发生和发育过程。结果表明:该属植物所有的萼片、花瓣、雄蕊和雌蕊均为螺旋状发生,花器官排列式样也为螺旋状; 5枚萼片原基宽阔,5枚花瓣原基圆球形、位于萼片原基的间隔,且在后期表现为延迟发育现象,雄蕊原基较小、为圆球形; 花瓣原基和雄蕊原基连续发生,无明显的时空间隔,但与萼片原基有时空间隔; 心皮原基为马蹄形对折,柱头组织由单细胞乳突组成; 胚珠倒生、具单珠被。该属花器官螺旋状排列、胚珠具单珠被在唐松草亚科中是独有的性状,花发育形态学证据支持了该属的特殊性。     

Correlations between proton-efflux patterns and growth patterns during geotropism and phototropism in maize and sunflower

By placing seedlings of sunflower (Helianthus annuus L.) or maize (Zea mays L.) on agar plates containing a pH indicator dye it is possible to observe surface pH patterns along the growing seedling by observing color changes of the indicator dye. Using this method we find that in geotropically stimulated sunflower hypocotyls or maize coleoptiles there is enhanced proton efflux on the lower surface of the organ prior to the initiation of curvature. As curvature develops the pattern of differential acid efflux becomes more intense. A similar phenomenon is observed when these organs are exposed to unilateral illumination, i.e. enhanced acid efflux occurs on the dark side of the organ prior to the initiation of phototropic curvature and the pattern of differential acid efflux intensifies as phototropic curvature develops. These observations indicate that differential acid efflux occurs in response to tropistic stimuli and that the acid efflux pattern may mediate the development of tropistic curvatures.     

Viability and mushroom production of Lentinula edodes and L. boryana strains (Fungi: Basidiomycetes) after cryogenic storage of spawn stocks

The viability of two strains of Lentinula edodes and two of L. boryana under cryogenic storage during 1 week has been studied from the evaluation of five contact periods (1, 1.5, 2, 3 and 5 h) of the cryoprotector, glycerol 10% (v/v), with the mycelium. On average, 99.25% of samples were recovered, 1.5 h being the best contact period. Afterwards, samples of the strains, before and after the cryogenic process, were cultivated at a pilot plant using a mix of Carpinus carolineana sawdust, rice bran and sorghum grains as substrate. The evaluation parameters were: days of incubation, primordia initiation, number of flushes, fruiting body sizes and biological efficiency (EB). Only L. edodes developed carpophores. On average, 3–4 flushes were obtained, which reached EB of 67.1 ± 30.7 to 74.7 ± 24.5 with no statistical differences detected between the yields. The majority of fructification sizes ranged from 5 to 14.9 cm. Morphological differences between the samples before and after the treatment were not observed.     

Flight activity assessment of the egg parasitoidTrichogramma brassicae (Hym.: Trichogrammatidae) in laboratory and field conditions

A laboratory and a field test for flight initiation ofTrichogramma brassicae Bezdenko (Hymenoptera, Trichogrammatidae) (synonymous toT. maidis Pintureau et Voegele) were developed with the aim to establish a simple, cheap and quick flight quality control method forTrichogramma producers. The flight quality of four strains ofT. brassicae reared onEphestia kuehniella Zeller eggs were compared. The material tested consisted of four strains: two strains reared for two (F2) and 39 to 42 (F39–42) generations onE. kuehniella eggs without storage treatment, a diapause strain reared six generations (F6) onE. kuehniella eggs and a commercial strain also reared onE. kuehniella eggs whose production and storage conditions were unknown. Clear differences in flight activity among strains were observed. Both, the F2 and commercial strain showed significantly better flight activity under laboratory conditions compared to the other strains. Flight field cage experiments were made for comparison between field and laboratory results. Similar differences among strains in field cage experiments were observed when compared to laboratory tests.     

Translation initiation by non-AUG codons in Arabidopsis thaliana transgenic plants

The efficiency of translation initiation at codons differing at one or two nucleotides from AUG was tested as initiation codons for the phosphinotricin-acetyltransferase gene in T-DNA plant transformation in Arabidopsis thaliana. With the exception of UUA codon that differs from AUG at two nucleotides and does not permit any detectable activity, all the other codons (AUC, GUG, ACG, and CUG) present a phosphinotrycin acetyltransferase activity that varies between 5 and 10% of the AUG activity. This low activity is sufficient to confer glufosinate resistance to some of the plants. These results indicate that, in plants as is the case in animals, non-AUG initiating codons may be used for translation initiation, namely when a low expression rate is needed.     

Effects of kanamycin on tissue culture and somatic embryogenesis in cotton

The aminoglycoside antibiotic kanamycin was evaluated for its effects on callus initiation from hypocotyl and cotyledon explants, proliferation of non-embryogenic and embryogenic calli, initiation and development of somatic embryos in cotton (Gossypium hirsutum L.). On this basis, the potential use of kanamycin as a selective agent in genetic transformation with the neomycin phosphotransferase II gene as the selective marker gene was evaluated. Cotton cotyledon and hypocotyl explants, and embryogenic calluses were highly sensitive to kanamycin. Kanamycin at 10 mg/L or higher concentrations reduced callus formation, with complete inhibition at 60 mg/L. Kanamycin inhibited embryogenic callus growth and proliferation, as well as the initiation and development of cotton somatic embryos. The sensitivity of embryogenic callus and somatic embryos to kanamycin was different during the initiation and development stages. Kanamycin was considered as a suitable selective agent for transformed callus formation and growth of non-embryogenic callus. Forty to sixty mg/L was the optimal kanamycin concentration for the induction and proliferation of transformed callus. The concentration of kanamycin must be increased (from 50 to 200 mg/L) for the selection of transformation embryogenic callus and somatic embryos. A scheme for selection of transgenic cotton plants when kanamycin is used as the selection agent is discussed.     

Predicting the intensity of the birch pollen season

We present a model for the prediction of the magnitude ofBetula flowering and pollen dispersal which may be used in the management of birch pollinosis and in the planning of clinical trials. The pollen sum during the flowering season is regressed on the temperature sum from May 1st to July 20th during the initiation year, the pollen sum of the initiation year, and the temperature sum during the main pollen season in the flowering year. We suggest that the fluctuating flowering pattern inBetula alba-species is primarily determined by the availability of assimilation products during inflorescence initiation and development during the spring one year before anthesis. When inflorescences, which are initiated during the previous year, elongate in the beginning of anthesis, they act as strong sinks to stored carbohydrates, and thus compete with developing leaves and shoots. The result is an initially reduced photosynthetic capacity in years with intense flowering, and a limited potential for the initiation of new inflorescences for the following year. The ambient temperature during catkin initiation affects assimilation efficiency and is a determinant of about equal importance to flowering intensity as is the magnitude of the flowering in the initiation year. The amount of pollen dispersed is also dependent on the weather during anthesis, which is not possible to predict until about one month in advance. The two other independent variables are available during the previous summer, making it possible to give a sufficiently valid prediction to allergologists about the magnitude of the next birch pollen season, according to its botanical determinants. We suggest that the varying reproductive output inBetula alba should not be described as true masting. A more parsimonious explanation to the flowering pattern is that an individual continually maximizes reproductive effort, according to what is possible, but that reproduction is often constrained by the environment.     

Predicting the intensity of the birch pollen season

We present a model for the prediction of the magnitude ofBetula flowering and pollen dispersal which may be used in the management of birch pollinosis and in the planning of clinical trials. The pollen sum during the flowering season is regressed on the temperature sum from May 1st to July 20th during the initiation year, the pollen sum of the initiation year, and the temperature sum during the main pollen season in the flowering year. We suggest that the fluctuating flowering pattern inBetula alba-species is primarily determined by the availability of assimilation products during inflorescence initiation and development during the spring one year before anthesis. When inflorescences, which are initiated during the previous year, elongate in the beginning of anthesis, they act as strong sinks to stored carbohydrates, and thus compete with developing leaves and shoots. The result is an initially reduced photosynthetic capacity in years with intense flowering, and a limited potential for the initiation of new inflorescences for the following year. The ambient temperature during catkin initiation affects assimilation efficiency and is a determinant of about equal importance to flowering intensity as is the magnitude of the flowering in the initiation year. The amount of pollen dispersed is also dependent on the weather during anthesis, which is not possible to predict until about one month in advance. The two other independent variables are available during the previous summer, making it possible to give a sufficiently valid prediction to allergologists about the magnitude of the next birch pollen season, according to its botanical determinants. We suggest that the varying reproductive output inBetula alba should not be described as true masting. A more parsimonious explanation to the flowering pattern is that an individual continually maximizes reproductive effort, according to what is possible, but that reproduction is often constrained by the environment.