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; )     

Auxin-induced heritable variants in yeast with special reference to physiological and genetic characters

A high concentration (400 mg/l) of an auxin, -naphthaleneaceticacid produced heritable variants differing in cell form andsize and in sporulation ability in a diploid strain of Saccharomycescerevisiae. These variants showed altered absorption spectrain the region of cytochromes a + a₃, b and/or c, but could growin a glycerol medium. Cultures of dissected spores from thesevariants involved many non-maters. These variants showed irregularsegregation of nutritional markers and/or a high DNA contentper cell. Since most of the variants grow more slowly on anauxin medium than does the original strain, they seem to beproduced by the induction by auxin rather than by selectiveenrichment. Genetic control of the ability to respond to auxinand the biological significance of auxin-induced variation inyeast is discussed. (Received January 12, 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; )     

Breeding season, courtship behaviour, and territoriality of White and Japanese Wagtails Motacilla alba and M. grandis

The breeding ecology of White and Japanese Wagtails, Motacilla alba and M. grandis , was studied along a river in central Japan. The home ranges of the two species greatly overlapped along the river, but no interbreeding occurred. M. grandis spent more time on the river than M. alba and defended territories there. M. alba used the river as part of the entire home range, and did not defend the river areas as territories. Singing activity and breeding started earlier in M. grandis than in M. alba. The early breeding of M. grandis was related to the lack of moulting in spring, less necessity for pair formation due to the existence of pairs in the winter, and the greater dependency on larval than on adult insects. Songs were very different between the two species. The bowing display that preceded the pre-copulation display was found only in M. alba. During the pre-copulation display, male M. grandis lifted both wings above the horizontal while male M. alba drooped both wings. The pre-copulation display of M. grandis was similar to that of Large Pied Wagtails M. maderaspatensis in India, suggesting a closer relationship of the two species than to M. alba.     

Development of spermiduct and seminal vesicle during pharate adult of the cabbage armyworm,Mamestra brassicae, (Lepidoptera; Noctuidae)

Summary

Development of the upper vas deferens and seminal vesicle, and the ecdysteroid titers of the cabbage armyworm (Mamestra brassicae) during pharate adult stage were investigated to provide evidence of endogenous control of the sperm movement through the reproductive tract. Apparently, development of the upper vas deferens is initiated when ecdysteroid titers increase after pupation and continues until eclosion. Sperm movement correlates with the decrease of ecdysteroid titers. When ecdysteroid titers remained at low levels, sperm release from the testis was observed one day before eclosion.     

RESPONSIVENESS OF YEAST CELLS TO AUXIN, ANIMAL SEX HORMONES AND YEAST SEXUAL HORMONES IN RELATION TO SEX CONTROLLING GENES

Genetic control of the ability of yeast cells to respond to cell-expanding action of animal, plant and yeast hormones was studied. Mating type specificity in the ability to respond to yeast sexual hormones was changed by introduction of homothallism-controlling genes, D and HM. Auxin, a plant hormone can expand cells of most homothallic strains, but not those of heterothallic strains as far as tested. Animal sex hormones showed the action similar to that of yeast sexual hormones.     

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; )     

The Participation of Speract in the Acrosome Reaction of Hemicentrotus pulcherrimus

A speract-free macromolecular fraction was prepared from the egg jelly of the sea urchin Hemicentrotus pulcherrimus by gel filtration and tested for ability to induce the acrosome reaction in H. pulcherrimus spermatozoa with or without exogenously added synthetic speract. The macromolecular fraction without speract showed only about half the activity of the original unfractionated jelly for induction of the acrosome reaction. The rates of the acrosome reaction induced by the fraction with speract were comparable with those induced by the unfractionated jelly at all pHs tested. Speract itself, however, did not induce the acrosome reaction in the absence of the macromolecular fraction of jelly. The acrosome reaction was associated with incerase of the cyclic AMP concentration in sperm cells, the extent of incerase depending on the concentration of the macromolecular fraction. Addition of speract to the fraction enhanced both induction of the acrosome reaction and increase in the cyclic AMP concentration induced by the fraction. These results suggest that a major factor(s) responsible for the acrosome reaction is a macromolecular component(s) of the jelly and that speract promotes the reaction as a co-factor.