DORMANCY OF GLADIOLUS CORMS VI. EFFECTS OF TEMPERATURE TREATMENT ON BREAKING DORMANCY OF GLADIOLUS CORMS STORED IN A STORAGE ROOM AND OF THOSE GROWN UNDER DIFFERENT DAY-LENGTH

A high temperature treatment at 35? for 5 days followed by alow temperature treatment at 0-5? for 25 days was given at fifteen-dayintervals to five groups each of two varieties (White Gold andCardinal Prince) stored in a storage room from September 27to November 26. The temperature treatment was apparently effectivefor sprouting of corms of both varieties at earlier period,but rather inhibitory at later period of dormancy. The plants of two varieties (Early Red and Spot Light) grownunder short day-length (9 hr) showed slightly earlier floweringand corm-forming than those grown under natural long day-length.These plants were harvested from July 1 to Septmber 1 at twentydayintervals, and sprouting of their corms with and without temperaturetreatment similar to the previous method was investigated. SpotLight corms did not sprout irrespective of temperature treatment.Early Red corms always sprouted earlier in the temperature-treatedlots, whereas they sprouted a little later in the non-treatedlots. The temperature treated corms grown under the short day-lengthshowed delaying and low percentage of sprouting. On the contrary,in the non-treated lots, sprouting of corms grown under thelong day-length was slower than those grown under the shortday-length. ¹Contribution No. 24 from Laboratory of Horticulture (Olericultureand Floriculture), Kyoto University. (Received May 23, 1960; )     

Differential fluorescent-banding patterns in chromosomes of four species of Cycas (Gycadaceae)

Similar karyotypes of In = 22 in Cycas circinalis, C. media var. basaltica, C. revoluia var. rewluta, C. revoluta var. taiwaniana and C. siammsis were compared with each other by using the CMA and DAPI fluorescent staining methods. Their four largest submedian-centromeric chromosomes each had a CMA band at the terminal region in common. Their 12 terminal-centromeric chromosomes commonly displayed CMA bands at the terminal region and the pericentric region. Two of the 12 terminal-centromeric chromosomes carried a CMA band somewhere in the interstitial region of the long arm. C. circinalis alone showed it at a relative position closer to the centromere. The other taxa showed it at a relative position near the terminal region. All of the chromosomes exhibited the DAPI dot at the centromeric region.     

Studies on germination of chrysanthemum pollen II. Occurrence of a germinationpromoting substance

The in vitro germination of chrysanthemum pollen is promotedby adding floral organs, excepting anther, to a basal mediumconsisting of sucrose and boric acid. Some other plant organs,such as young fruit of tomato and onion bulb, are also effective.In Chrysanthemum morifolium, the percentage of pollen germinationin the presence of such plant tissues is two to three timesas high as in the control (10 %). In Ch. leucanthemum, it ishigher than 50 %, in contrast to the control in which no germinationis noted. This promotion of germination may be due to a substance extractablefrom the tissues with water, ether or methanol. The promoting substance is not identical with several knowngrowth regulators or with the Ca ion. (Received November 21, 1967; )     

Parthenogenetic development of dwarf surf dam,Mulinia lateralis,oocytes treated with polar body suppressing agents

Summary

Parthenogenesis following oocyte activation has been observed in a number of marine invertebrates, but the fate of parthenogenesis in bivalve mollusc embryos is unclear. We used the dwarf surf clam, Mulinia lateralis, to examine parthenogenetic development of KC1-activated oocytes using the polar body suppressing agents caffeine and heat or cytochalasin B. Development was followed by epifluorescence microscopy and flow-cytometric analysis using the DNA-specific fluorochrome DAPI. All agents suppressed polar body formation to some degree, putatively increasing the ploidy level and retaining a meiotic centrosome in the zygote; but the zygotes failed to develop normally. Failure of the zygotes to develop suggests that the meiotic centrosome is incapable of participating in mitosis in bivalves.     

Functional Properties of Cloned Melanogenic Proteins

Several genes critical to the regulation of melanin production in mammals have recently been cloned and characterized. They map to the albino, brown, and slaty loci in mice, and encode proteins with similar structures and features, but with distinct catalytic capacities. The albino locus encodes tyrosinase, an enzyme with three distinct catalytic activities—tyrosine hydroxylase, 3,4-dihydroxyphenylalanine (DOPA) oxidase and DHI (5,6-dihydroxyindole) oxidase. The brown locus encodes TRP-l (tyrosinase-related protein-I), which has the same, but greatly reduced, catalytic potential. The slaty locus encodes TRP-2, another tyrosinase related-protein, which has DOPAchrome tautomerase activity. In this study we have examined the enzymatic interactions of these proteins, and their regulation by a novel melanogenic inhibitor. We observed that tyrosinase activity is more stable in the presence of TRP-l and/or TRP-2, but that the catalytic function of TRP-2 is not affected by the presence of TRP-1 or tyrosinase. Other factors also may influence melanogenesis and a unique melanogenic inhibitor suppresses tyrosinase and DOPAchrome tautomerase activities, but does not affect the spontaneous rate of DOPAchrome decarboxylation to DHI. The results demonstrate the catalytic functions of these proteins and how they stably interact within a melanogenic complex in the melanosome to regulate the quantity and quality of melanin synthesized by the melanocyte.     

Changes in Endogenous Growth Regulators in the Gladiolus Corm during Dormancy

Changes in endogenous growth regulators in gladiolus corms during dormancy were studied using paper and column chromatography followed by a bioassay with the test for straight growth of Avena coleoptile. Corms were grown in the field or in a glass room of a phytotron at 20°C in the light. Another lot was grown in a dark room at 20°C in the dark. Half of the daughter corms in each lot were cold-treated for about one month and the other half were stored at room temperature after harvest. The earliest sprouting was seen in dark grown corms with cold treatment, and the latest sprouting in light grown corms without cold. This pattern was similar in each cultivar over a period of three years. Corms from both lots contained considerable amounts of inhibiting substance just after harvest. However, dark grown corms treated with cold showed a rapid decrease in inhibitor activity and an increase in promoter activity. On the other hand, in light grown corms without cold treatment there was inhibitor activity found consistently even after two months. —There appear to be two inhibiting zones in the chromato-grams. One of these contains two inhibitory substances, one of which was assumed to be abscisic acid.     

Morning dew and Tripospermum (Hyphomycetes)

Morning dew appears to be an important factor in the habitat of Tripospermum species. It affects both conidial development and liberation.     

FLAVOPROTEINS IN THE LEAVES OF HIGHER PLANTS CATALYZING THE OXIDATION OF L-GLUTAMATE

1. Two forms of enzyme capable of catalyzing the oxidation of L-glutamate(and L-aspartate) were isolated from the leaves of spinach andseparated from each other by column-chromatographic purificationon calcium phosphate and anion exchangers. They were distinguishedas GD₁ (L-glutamate dehydrogenase 1) and GD₂ (L-glutamate dehydrogenase2). The purification procedures and some fundamental propertiesof the partially purified enzymes were investigated.
2. It wasdiscovered that the enzymes did not require any cofactor,ie., neither dialysis nor precipitation with ammonium sulfatecaused a fall in enzyme activities and the addition of DPN andTPN to the reaction mixture did not accelerate the reactionrate
3. From the results of spectroscopic investigation GD₁ andGD₂were shown to be flavoproteins, although their prostheticgrouphas not yet been identified The activity of GD₁ was enhancedby the addition of FAD or FMN, while GD₂ was not acceleratedby these factors.
4. The characteristics of the two enzymes includingsubstrate specificity,MICHAELIS constant, optimum pH of thereaction and specificityfor electron acceptors were compared.
5. From the stoichiometric study of the oxidation of L-glutamatewith these enzymes, it was confirmed that the reaction is representedby the following equation: L-glutamate+oxidized dye+h₂o
6. Among various inhibitors tested,molecular oxygen which couldfunction as electron acceptor ofL-glutamate oxidation in thepresence of GD₁ was found to causea strong inhibition uponthe same reaction with TTC as el acceptor.The inhibition wasconfirmed to be due to hydrogen peroxideproduced as a resultof the aerobic oxidation of L-glutamate.

(Received July 25, 1962; )     

Reductive carboxylation and amination of keto acids by spinach chloroplasts

1. In spinach chloroplasts, the occurrence of malic enzyme,isocitrate dehydrogenase, glutamate dehydrogenase and alaninedehydrogenase was confirmed. 2. In the presence of ammonia, pyruvate and -ketoglutarate andpyruvate were photoreductively aminated to glutamate and alanine,respectively. 3. In the absence of ammonia, pyruvate and -ketoglutarate werephotoreductively carboxylated to malate and isocitrate, respectively. 4. Photoreductive carboxylation of pyruvate and -ketoglutaratewas suppressed by molecular oxygen. Inhibition was partly dueto oxidation of photoreduced NADP or NAD. (Received August 4, 1969; )     

Studies on flower color in Chrysanthemum morifolium RAMAT. I. Anthocyanins

Isolation and characterization of anthocyanins from the flowersof two cultivars of Chrysanthemum morifolium RAMAT. are reported.The main pigment is a new glucoside of cyanidin. ¹Cultivated at the Kyoto University Agricultural ExperimentalFarm (Received October 25, 1969; )