Studies on the change of the respiratory system in roots in relation to the growth of plants II. Activity of iron-containing oxidases in roots of cereal crops with the aging of plants

Distribution of iron-containing oxidases in aging nodal rootsof rice and wheat was studied. Activities of cytochrome c oxidase(1.9.3.1 [EC] , cytochrome c : O₂ oxidoreductase), catalase (1.11.1.6 [EC] ,H₂O₂: H₂O₂ oxidoreductase) and peroxidase (1.11.1.7 [EC] , donor:H₂O₂ oxidoreductase) in wheat roots were comparatively higherthan were those in rice roots at corresponding stages. Cytochromec oxidase in roots remained active throughout the lives of therice and wheat crops. In rice roots, catalase seemed to playa distinct role around the panicle formation stage. Decay ofcatalase activity took place earlier than did that of peroxidaseand cytochrome c oxidase activities. In wheat roots similarenzyme activity changes were not observed. Data may suggestthat the high activity of iron containing oxidases at the panicleformation stage (I) may be chiefly due to catalase activityin rice roots. ¹Paper presented at the 14th Annual Meeting of the Society ofthe Science of Soil and Manure, Japan (1968). (Received November 21, 1968; )     

PHOTOOXIDATIVE CONSUMPTION AND PHOTOREDUCTIVE FORMATION OF ASCORBIC ACID IN GREEN LEAVES

1. From leaves of barley and spinach, cellular components wereisolated and brought together under various conditions to investigatethe fate of ascorbic acid as affected by the components in thelight and dark. 2. A new colorimetric method for assaying ascorbic acid andsome other reducing substances was devised, measuring the colorof molybdenum-blue developed by the substances in the presenceof excess amounts of phosphomolybdate and inorganic acid. 3. The photooxidation of ascorbic acid by green and yellow filtrates,prepared from green and etiolated leaves of barley, was studiedby the ordinary as well as the new colorimetric method. In thepresence of oxygen, the oxidation of ascorbic acid was foundto be accelerated by light in the green filtrate, but not inthe yellow filtrate. 4. The oxidation of the endogenous reducing substance containedin the supernatant fraction of spinach leaf extracts was studiedin the presence of washed chloroplasts (spinach). In the presenceof oxygen, the rate of oxidation in the light was markedly higherthan in the dark. From the changes in absorption spectrum accompanyingthe reaction, the endogenous reducing substance in questionwas identified as ascorbic acid. 5. The occurrence of an endogenous precursor of ascorbic acidin spinach leaf extracts was disclosed. The photoreduction ofthis precursor into ascorbic acid was studied in the precenceof spinach chloroplasts. A specific inhibition of this reactionby phosphoglycerate and glycerophosphate was discovered. 6. The experimental results obtained were discussed in connectionwith the role of ascorbic acid in photosynthesis. (Received September 13, 1960; )     

ENDOGENOUS CHANGES OF PHOTOCHEMICAL ACTIVITIES OF SPINACH LEAVES

The activities of green cell-free extracts of spinach leavesin performing photochemical transphosphorylation, photosyntheticphosphorylation, the HILL reaction and the light-induced formationof the endogenous reducing substance (ascorbic acid) were followedin parallel during the growth process of the plant. There wasa certain parallelism between the development of the activitiesof photochemical transphosphorylation, of photo-synthetic phosphorylationand of the HILL reaction, activities being low in the earlierstage of growth, reaching a maximum just before efflorescence,and showing thereafter a more or less sharp decline. The activityin the light-induced formation of endogenous reducing substancewas undetectable for the first 35 day-period of growth, reacheda maximum about one week earlier than the other three activities,and again disappeared after 60 days of growth. (Received September 9, 1960; )     

Studies on the change of the respiratory system in roots in relation to the growth of plants V. Effect of root pruning terminal oxidase activity in roots of cereal crops

This experiment studies the comparative activities of terminaloxidases (Fe-containing oxidases, Cu-containing oxidases andCN-resistant oxidases) in roots of rice and wheat seedlingsand the effect of root pruning on these terminal oxidases inthe roots of those crops. Data indicate that (i) excepting achange in the activity of Cu-containing oxidases no appreciabledifference in respiration or in Fe-containing and CN-resistantoxidases was noticed in the two types of seedling roots and(ii) root pruning did not produce any noticeable change in terminaloxidase activities in roots of wheat seedlings. A drastic changein terminal oxidase activities in roots of rice seedlings wasobserved, suggesting that a close relationship exists betweenCN-resistant oxidase and transplanting time. (Received November 21, 1968; )     

Distributions of Actin, Vinculin and Fibronectin in the Duodenum of Developing Chick Embryos: Immunohistochemical Studies at the Light Microscope Level

Microscopic studies were made on the localizations of three different cytoskeletal proteins, actin, vinculin and fibronectin, in the duodenum of developing chick embryos and chicks by an indirect immuno-fluorescent staining method with specific antibodies.
Topographical changes in the distributions of these three proteins seemed to be related to stages in morphogenesis of the duodenum. In early stages of embryonic development, findings suggested interaction between actin and vinculin in the apical region of epithelial cells and between actin and fibronectin in the basal region of these cells. From this stage, vinculin and fibronectin seemed to be of importance in determination and continuity of the polarity of the duodenal epithelium, and in control of the intracellular arrangement of actin. This relation between actin and vinculin seemed to continue throughout embryogenesis.
The main role of actin in epithelial cells seemed to change on day 12 from that of forming constricting bundles for morphogenesis of previllous ridges to that of microfilaments in the microvilli and the terminal web.     

Host range of Asobara japonica (Hymenoptera: Braconidae), a larval parasitoid of drosophilid flies

We studied the host range of Asobara japonica, a larval‐pupal parasitoid of drosophilid flies. Habitat selection was found to be an important determinant of host range in this parasitoid; it attacked drosophilid larvae breeding on banana and mushrooms, but seldom attacked those breeding on decayed leaves. This parasitoid was able to use diverse drosophilid taxa as hosts. Attack by A. japonica sometimes killed hosts at the larval stage, and therefore parasitoid larvae also died. Drosophila elegans and D. busckii suffered particularly high larval mortality due to the attack by A. japonica (in the latter species only when young larvae were attacked). Many individuals of D. subpulchrella also died at the pupal stage without producing parasitoids when they were parasitized at the late larval stage. In contrast, D. bipectinata, D. ficusphila, D. immigrans, D. formosana and D. albomicans were resistant to attack: large proportions of the larvae of these drosophilid species grew to adulthood, even in the presence of parasitoids. On the basis of phylogenetic information, we concluded that phylogenetic position has only limited importance as a factor determining whether a species is suitable as a host for A. japonica, at least within the genus Drosophila.     

ROLE OF CALCIUM IN POTASSIUM UPTAKE BY PLANT ROOTS

The effects of EDTA·Mg or GEDTA·Mg on the uptakeof nutrient ions, the release of Ca⁺⁺ and nucleotides into themedium and the nucleic acid contents in rice and red bean rootswere investigated.

1. Both EDTA and EDTA·Mg induced similarly the release ofCa from roots.
2. EDTA·Mg as well as EDTA brought abouta significant repressionin K uptake, but had an insignificantor no effect on P, NH₄and NO₃ uptakes. EDTA·Ca did notrepress K, P, NH₄ andNO₃ uptakes.
3. EDTA or GEDTA acceleratedthe degradation of nucleic acid andthe release of nucleotides,while EDTA·Mg or GEDTA·Mghad no such effect.

These results indicate that the indispensable role of intracellularCa in K uptake does not appear to be directly associated withRNA metabolism. (Received July 29, 1965; )     

Long‐term isolation of the coastal plant Calystegia soldanella (Convolvulaceae) in ancient freshwater Lake Biwa,Japan

Lake Biwa is an ancient freshwater lake that was formed approximately 4 Mya and harbours many coastal plants that commonly inhabit the seashore. We used chloroplast DNA haplotype analysis using two spacer sequences and simple sequence repeat (SSR) analysis using eight nuclear microsatellite markers to detect genomic signatures indicating long‐term isolation of inland populations of Calystegia soldanella in Lake Biwa from coastal populations. We used 348 samples from 63 populations for haplotype analysis and 478 samples from 27 populations for SSR analysis covering the inland and coastal distribution of the species. We detected seven haplotypes, and the distribution pattern of these haplotypes was geographically highly structured between Lake Biwa and the coast. Nuclear SSR analysis also supported genetic differentiation between Lake Biwa and coastal populations (analyses of molecular variance, 43%), and the grouping of Lake Biwa and coastal populations by a Neighbour‐joining tree. In addition, genetic diversity of the inland populations (mean H_E = 0.153) was significantly lower than that of coastal populations (mean H_E = 0.328). These results suggested that inland populations at Lake Biwa have been isolated from coastal populations for a very long time. The inland populations most likely experienced a bottleneck effect, resulting in sufficient in situ genetic divergence to clearly distinguish them from coastal populations. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 102 , 51–66.     

Seasonal life cycles and resource uses of flower- and fruit-feeding drosophilid flies (Diptera: Drosophilidae) in central Japan

Seasonal life cycles and resource uses of flower- and fruit-feeding drosophilids (Diptera: Drosophilidae) were studied from low to high altitudes in central Japan to understand their adaptation to seasonal changes of environmental conditions. Drosophila unipectinata and D. oshimai specialized to flowers, D. suzukii and D. subpulchrella depended almost on fruits, while D. lutescens , D. rufa , D. auraria , D. biauraria and D. sternopleuralis used both of them. It was assumed that D. unipectinata moved from low to high altitudes in June while D. oshimai , D. suzukii and D. subpulchrella in July. Migration of D. unipectinata is considered as a means to avoid summer heat or exploit early-summer resources at high altitudes. On the other hand, D. oshimai , D. suzukii and D. subpulchrella have the capacity to pass the summer at low altitudes, and therefore their migration is assumed as a means to escape from resource-poor conditions in summer at low altitudes or exploit resources at high altitudes. The generalist species, D. lutescens , D. rufa , D. auraria , D. biauraria and D. sternopleuralis , would not perform such extensive movements between low and high altitudes. They may pass the summer at low or mid altitudes depending on accidentally fallen immature fruits and/or some other resources such as decayed leaves.