Study on the Structure and Genetic Polymorphism of Embryo Sac in Polyembryonic Rice Strain AP Ⅳ

By using the technology of GMA half-section the comparative studies on the structure of embryo sac between polyembryonic rice strain AP IV and haploembryonic rice cuhivar “IR36” showed: In AP IV, except 7.8% of ovaries in which the embryo sac degenerated, there were only 27.1% of ovaries in which the structure of embryo sac was similar to that of "IR36' which was of the Polygonum type; 65.1 % of ovaries were different from “IR36”, in which some changes happened in the embryo sac: Of most two kinds of variant embryo sac, referred as poly-egg apparatus embryo sac (53.3%) and double set of embryo sac (6.3%) were found. In the poly-egg apparatus embryo sac, three egg-apparatuses were the majority which could be further divided into three types, namely, 5-2-1 type, 6-2-0 type and 5-3-0 type, based on the whole structure of embryo sac. The double set of embryo sac characterized with a large embryo sac inlaid with a small embryo sac, and with the eggs far from the micropyle part. Moreover, the other variants were also found. According to the analysis, genetic polymorphism of the structure of embryo sac was found in single-panicle in AP Ⅳ.     

Formation and Development of Different Types of Embryo Sacs in Polyembryonic Rice Strain APⅣ

The process of different types of embryo sac formation was studied in AP IV by using the technic of seni-thin sectioning. Different types of embryo sacs were formed by different ways of development. The embryo sac of 5-2-1 type, 6-2-0 type, and 5-3-0 type were formed through three respectively new Polygonum-variant ways of development. The factors causing the three different ways of development were positional change of functional megaspore nucleus, change of orientation of the dividing-spindle of the embryo sac nucleus, nonsynchronous division of embryo sac nucleus and orientation of nucleus after division. Double set of embryo sac resulted possibly from mutual change in position of the primordial low polar nucleus and the primordial egg cell, i. e. the polar nucleus did not move toward the center of the embryo sac, but remained in the micropyle part, whereas the egg cell moved to the center and replaced the low polar nucleus.     

Fertilization of Different Types of Embryo Sacs and Its Embryo Formation in Polyembryonic Rice Strain APⅣ

The ferflization and its embryo fonnation of different types of embryo sacs were studied by using the technology of GMA half-section in the APIV strain of polyembryonic rice ( Oryza sativa L. ). In rare cases,all three egg cells in the embryo sac of 5-2-1 type could fertilize and develop into three embryos. But in most cases only one or two egg cells fertilized and developed into one or two embryos in the respective type of embryo sac. The frequency of poly-egg fertilization in total all was very low in the embryo sac of 6-2-0 type and 5-3-0 type. These results indicated that the polyembryos in APIV originated mainly from overall fertilization and develotment of the embryo sac with poly-egg apparatus. This was observed,for example, in 5-2-1 type in which three embryos were fertilized and developed from three egg cells and two embryos from two egg cells. The fertlization process of double set of embryo sac was most complicated, all often abnormal. Only in few ovaries the egg cells in both large and small embeyo sac could fertilize simultaneously. The fertilization and development of egg cells in the large embryo sac might be the main cause of the formation of the so called "mid-seated embryo" (the embryo far from the micropyle end).     

Localization of γ Globulin in Rice Seed and Changes in γ Globulin Content during Seed Development and Germination

Three components of γ globulins, γ₁ γ₂ and γ₃, in rice seed were investigated immunochemically. γ₁ Globulin was found to be immunochemically distinct from γ₃ globulin because the immuno-precipitin arcs crossed, while γ₂ globulin was immunochemically identical with γ₃ globulin as γ₂ globulin reacted with the anti-γ₃ globulin-serum. It was revealed by means of fluorescent-antibody technique that both γ₁ and γ₃ globulins were localized in scutellum and aleurone cells. The content of γ₁ globulin in aleurone cells was higher than that in scutellum, while the relative contents of γ₃ globulin in these tissues were in the reverse relation. During seed development, γ₁ and γ₃ globulins increased almost linearly from the 5th day to the 40th day after flowering. On the other hand, the amounts of γ₁ and γ₃ globulins decreased rapidly in the process of germination. The rate of disappearance of γ₃ globulin was greater than that of γ₁ globulin.     

The Fertilization and the Development of Embryo and Endosperm in an Endangered Plant—Ranalisma rostratum Stapf (Alismataceae)

Ranalisma rostratum Stapf is a rare and endangered species． This paper deals with the fertilization and the development of embryo and endosperm in this plant．The embryogenesis is of Caryophyllad type and the development of endosperm belongs to Heobial type．Before fertilization,the two polar nuclei are located respectively at both ends of embryo sac. In most angiosperms with two polar nuclei,the polar nuclei may fuse eiher before fertilization to form a secondary nucleus or during fertilization called triple fusion． In Ranalisma rostratum Stapf, however, it is found that only in case when the micropylar polar nucleus is fertilized,it can move to the chalazal end and fuse with the chalazal polar nucleus．This phenomenon is very rare and the process must take more time to fulfil fertilization both polar nuclei． This feature of fusion of polar nuclei is therefore thought as a primitive character from the view of phylogeny．     

Activities,Quantitative Changes and Subcellular Localization of |á-Amylase During Development of Apple Fruit

Starch degradation in cells is closely associated with cereal seed germination, photosynthesis in leaves, carbohydrate storage in tuberous roots, and fleshy fruit development. α-Amylase is considered as one of the key enzymes catalyzing starch breakdown, but up to date its role in starch breakdown in living cells remains unclear because the enzyme was often shown extrachloroplastic in living cells. The present experiment showed that α-amylase activity was progressively increasing concomitantly with the decreasing starch concentrations during the development of apple (Malus domestica Borkh cv. Starkrimson) fruit. The apparent amount of α-amylase assessed by Western blotting also increased during the fruit development, which is consistent with the seasonal changes in the enzyme activity. The enzyme subcellular-localization studies via immunogold electron-microscopy technique showed that α-amylase visualized by gold particles was predominantly located in plastids, but the gold particles were scarcely found in other subcellular compartments. A high density of the enzyme was observed at the periphery of starch granules during the middle and late developmental stages. These data proved that the enzyme is compartmented in its functional sites in the living cells of the fruit. The predominantly plastid-distributed pattern of α-amylase in cells was shown unchanged throughout the fruit development. The density of gold particles (α-amylase) in plastids was increasing during the fruit development, which is consistent with the results of Western blotting. So it is considered that α-amylase is involved in starch hydrolysis in plastids of the fruit cells.     

A Pact with the Embryo: Viktor Hamburger,Holistic and Mechanistic Philosophy in the Development of Neuroembryology, 1927–1955

Viktor Hamburger was a developmental biologist interested in the ontogenesis of the vertebrate nervous system. A student of Hans Spemann at Freiburg in the 1920s, Hamburger picked up a holistic view of the embryo that precluded him from treating it in a reductionist way; at the same time, he was committed to a materialist and analytical approach that eschewed any form of vitalism or metaphysics. This paper explores how Hamburger walked this thin line between mechanistic reductionism and metaphysical vitalism in light of his work on the factors influencing growth of neurons into limb buds, and the discovery of nerve growth factor, work carried out with Rita Levi-Montalcini and Stanley Cohen.     

Changes in Thermostability of Photosystem Ⅱ and Leaf Lipid Composition of Rice Mutant with Deficiency of Light-harvesting Chlorophyll a/b Protein Complexes

We studied the difference in thermostability of photosystem Ⅱ （PSII） and leaf lipid composition between a T-DNA insertion mutant rice （Oryza sativa L.） VG28 and its wild type Zhonghuau. Native green gel and SDS-PAGE electrophoreses revealed that the mutant VG28 lacked all light-harvesting chlorophyll a/b protein complexes. Both the mutant and wild type were sensitive to high temperatures, and the maximal efficiency of PSII photochemistry （FJ Fm） and oxygen-evolving activity of PSII in leaves significantly decreased with increasing temperature. However, the PSII activity of the mutant was markedly more sensitive to high temperatures than that of the wild type. Lipid composition analysis showed that the mutant had less phosphatidylglycerol and sulfoquinovosyl diacylglycerol compared with the wild type. Fatty acid analysis revealed that the mutant had an obvious decrease in the content of 16：1t and a marked increase in the content of 18：3 compared with the wild type. The effects of lipid composition and unsaturation of membrane lipids on the thermostability of PSII are discussed.     

Social Play or the Development of Social Behavior in Ferrets (Mustela putorius)?

Ferrets are the domesticated form of the European polecat. Changesin ferret kit, face to face orientation (en face) were describedfor littermate dyads at 46, 62, and 94 days after birth. Enface characteristics were discussed in terms of their appropriatenessfor reported burrow attachment and subsequent dispersal of polecatkits to illustrate both the transactional and the developmentalnature of our approach and to emphasize the neglected developmentalproblem of knowing the organization of kit behavior in its ecologicalsetting. This emphasis brings into question the appropriatenessof play criteria, reduces the heuristic value of play for thoseinterested in development, and suggests the importance of multipleendpoints for developmental investigations. Play also limitsdevelopmental investigations because of the nature of ethologicalbehavioral categories: Their adult, motivational, and evolutionaryemphases direct attention to "functional" rather than "analytic"questions. Although these questions are complementary, theyare not equally appropriate for problems of evolution and developmentbecause the former direct our attention of behavior of youngorganisms while the latter direct our attention to mechanismsof the developmental process. Our evaluation of play appliesequally well to other functional categories of behavior, suchas sexual and aggressive behavior.     

Oviposition Behavior of the Rice Brown Planthopper, Nilaparvata lugens (Stål), and Its Electronic Monitoring

Oviposition behavior of Nilaparvata lugens (Stål) (Homoptera: Delphacidae) on rice, Oryzae sativa L., was monitored using a videocamera and an AC (alternating-current) electronic measuring system. Oviposition by N. lugens always took place during stylet penetration into the plant. After penetration of the ovipositor, there were three specific ovipositional sequences observed; sawing insertion of the ovipositor, release of an egg in the plant, and partial or complete withdrawal of the ovipositor from the plant. Distinctive waveforms were recorded in correlating with these events. From a sequence of waveform patterns, it was possible to determine the number of eggs and egg masses laid inside the plant tissue and the duration of oviposition behavior. Waveform analysis revealed that N. lugens laid an egg mass consisting of on average 5.7 eggs. This occurred 4.3 min after a period of about 6.4 min of stylet penetration, and this sequence was repeated several times in 24 h. Electrical and/or tethering effects on oviposition appear to be negligible within 24 h of recording.     

Changes of Photosystem Ⅱ Electron Transport in the Chlorophyll-deficient Oilseed Rape Mutant Studied by Chlorophyll Fluorescence and Thermoluminescence

The photosystem Ⅱ (PSII) complex of photosynthetic membranes comprises a number of chlorophyll-binding proteins that are important to the electron flow. Here we report that the chlorophyll b-deficient mutant has de creased the amount of light-harvesting complexes with an increased amount of some core polypeptides of PSII,including CP43 and CP47. By means of chlorophyll fluorescence and thermoluminescence, we found that the ratio of Fv/Fm, qP and electron transport rate in the chlorophyll b-deficient mutant was higher compared to the wild type.In the chlorophyll b-deficient mutant, the decay of the primary electron acceptor quinones (QA-) reoxidation was decreased, measured by the fluorescence. Furthermore, the thermolumlnescence studies in the chlorophyll b deficient mutant showed that the B band (S2/S3QB-) decreased slightly and shifted up towards higher temperatures.In the presence of dichlorophenyl-dimethylurea, which is inhibited in the electron flow to the second electron acceptor quinines (QB) at the PSII acceptor side, the maximum of the Q band (S2QA-) was decreased slightly and shifted down to lower temperatures, compared to the wild type. Thus, the electron flow within PSll of the chlorophyll b-deficient mutant was down-regulated and characterized by faster oxidation of the primary electron acceptor quinine QA- via forward electron flow and slower reduction of the oxidation S states.     

Early Changes in Behavior Deficits, Amyloid β-42 Deposits and MAPK Activation in Doubly Transgenic Mice Co-expressing NSE-Controlled Human Mutant PS2 and APPsw

1. Doubly transgenic mice were some differences in the period proceeding of the development of Abeta-42 deposits and behavioral deficits. It was not characterized human mutant PS2 (hPS2) with APPsw in the brains of double transgenic mice. The aim of this study was to examine whether doubly transgenic mice co-expressing NSE-controlled APPsw and hPS2m develop AD-like phenotypes much earlier than singly APPsw or hPS2m alone. 2. We produced doubly transgenic mice from a cross between our previously created NSE-controlled hPS2m and an APPsw transgenic line. This doubly transgenic line was quantitatively produced by cross with age-matched control mice, and the produced mice were separated into 5, 6, 7 and 8-month old age groups. At the age of 8 months, the four groups of mice were tested for behavioral function, levels of Abeta-42 deposition, and potential signaling events. 3. It was shown that all the AD-like phenotypes, including behavior deficits, Abeta-42 levels, MAPK activation and ER expressions in doubly transgenic mice develop much earlier in the early time of AD development than their singly transgenic and non-transgenic littermates. 4. The results suggest that elevated Abeta-42 levels, and MAPK activation in doubly transgenic mice are model for early diagnosis and treatment of AD with therapeutic drug.     

Feeding Behavior, Habitat Use, and Abundance of the Angelfish Holacanthus passer (Pomacanthidae) in the Southern Sea of Cortés

Feeding behavior and habitat use of the king angelfish, Holacanthus passer, was studied in the southern Sea of Cortés, México. H. passer fed on benthic communities (algae and sessile invertebrates) and in the water column (mainly feces from the damselfish Chromis atrilobata). Although there were not significant differences in feeding rate between sexes, coprophagy was more common in males, while grazing was more common in females. Spatial distribution of size classes followed a pattern of decreasing size with increasing depth. Feeding rate was significantly different among habitats: small females had a higher feeding rate on the bottom, big females and small males had similar feeding rates from the bottom to 3m above the bottom, and big males had higher feeding rates from 5m above the bottom to the surface. Habitat was clearly partitioned, and there was significant habitat overlap only between big females and small males. The abundance of H. passer was partly explained (34% of the total variance) by the abundance of the damselfish C. atrilobata. There was a clear trophic association between C. atrilobata schools and H. passer feeding damselfish feces in the water column. The sex ratio male:female of H. passer populations was >1 at several sites, an unusual pattern for a protogynous fish. The sex ratio on the H. passer water column stock was also biased towards males at most sites. Although there is a positive relationship between C. atrilobata abundance and H. passer, there are factors other than damselfish abundance which cause this dominance of males.     

Progressive Effect of α-Phenyl-N-Tert-Butyl Nitrone (PBN) on Rat Embryo Development in Vitro

In the present study we demonstrated the effects of the spin-trapping agent α-phenyl-N-tert-butylnitrone (PBN) on the in vitro development of rat embryos at the early stage. In rat embryos, PBN increased the speed of the first cleavage and had no toxicity during pregnancy after embryo culture. These results showed that reactive oxygen species (ROIs) that were formed by activating molecular oxygens through redox reactions regulated the speed of development for early-stage embryos. Thus, PBN caused a decrease in the level of ROIs and toxicity and an in increase in the level of the development of rat embryos. On the other hand, PBN could not decrease the 2-cell block in vitro nor increase the blastulation rate, in contrast to the fact that a scavenger of superoxide anions, SOD, is effective in doing so for mouse embryos. From these results it was concluded that free radicals play an important role in the in vitro development of rat embryos at the early stage, but play no role in the decrease of the 2-cell block or their blastulation rate. It should be noted that PBN had no toxicity for embryonic development at the 2-cell stage.     

Pro-Environmental Behavior: Does It Matter How It’s Measured? Development and Validation of the Pro-Environmental Behavior Scale (PEBS)

Many empirical studies examine the performance of pro-environmental behavior. A review of 49 recent studies revealed 42 unique measures of pro-environmental behavior. Analysis of these studies indicates a lack of consistency among the various behavioral measures. To address the issue of inconsistency in such a critical variable, I developed a new measure, the Pro-Environmental Behavior Scale (PEBS). The behaviors included in this scale are those identified by environmental scientists as having the greatest impact on the environment. Principal components analysis generated a 19-item scale with four dimensions. Coefficient alpha for the full scale was .76. Coefficient alphas for the subscales ranged from .62 to .74. Bivariate Pearson correlations between the PEBS and the New Ecological Paradigm Scale, the Environment Identity Scale, and the Environmental Regulations Attitude Scale demonstrated the scale’s construct validity. Test-retest correlations were strong, demonstrating reliability of the PEBS.     

Changes in Structure,Composition, and Nutrients During 15 Yr of Hurricane-Induced Succession in a Subtropical Wet Forest in Puerto Rico

The trajectory of hurricane-induced succession was evaluated in a network of forest plots measured immediately before and 3 mo, 5, 10, and 15 yr after the direct impact of a Category 4 hurricane. Comparisons of forest structure, composition, and aboveground nutrients pools were made through time, and between species, life-history groups and geomorphic settings. The hurricane reduced aboveground biomass by 50 percent, causing an immediate decrease in stem density and diversity indices among all geomorphic settings. After 15 yr, basal area and aboveground biomass returned to pre-hurricane levels, while species richness, diversity indices, and stem densities exceeded pre-hurricane levels. Differences in species composition among geomorphic settings had not returned after 15 yr but differences in stem densities and structure were beginning to emerge. Significant differences were observed in the nutrient concentration of the three species that comprised the most aboveground biomass, and between species categorized as secondary high-light species and primary, low-light species. Species whose abundance was negatively correlated with the mature forest dominant also had distinct nutrient concentrations. When total aboveground nutrient pools were compared over time, differences in leaf nutrients among species were hidden by similarities in wood nutrient concentrations and the biomass dominance of a few species. The observed successional trajectory indicates that changes in species composition contributed to fast recovery of aboveground biomass and nutrient pools, while the influence of geomorphic setting on species composition occurs at time scales >15 yr of succession.