The plumule of the embryo of Sesamum indicum, which has a decussate shoot apex, was split by a vertical incision across the two primordia of the first pair of leaves. When the operated embryo was allowed to grow, these two members were displaced to the side of the incision of the apex and fused into a double-leaf. The process of the double-leaf formation can be explained in connection with the shoot regeneration, as follows. The halved plumule regenerates a new shoot by the formation of a new growing point on the lateral side of the original apex. As the new growing point grows bigger, the relative position of the first leaf-primordia in reference to the whole stem becomes closer together, and eventually two leaf-primordia fuse together into a double-leaf during their growth.
1. The quality and behaviour of nucleus have been studied in the rhizoid of Dryopteris erythrosora. 2. Very striking change of nuclear shape has been observed in a medium containing 2% sodium phosphate, and this change was reversible. 3. In Dryopteris, the cell-differentiation may be accompanied by the nuclear differentiation. 4. It has been discussed that the nucleus of rhizoids is not indispensable for the elongation. I wish to express my thanks to Dr. T. Shimamura for his cordial guidance during the work.
1. Four different types of the bud in the Japanese bamboos were distinguished based on the arrangement of prophyll in the bud, and they were named as follows: Sasa, Pleioblastus, Shibataea, and Phyllostachys Type. 2. All of the prophylls found in these types are two-keeled form, except in the Shibataea Type. 3. In the interpretation of the prophyll of Shibataea Type which seems to be seperated double prophylls, the writer is unable to agree with the fusion theory that the prophyll of the two keeled from is formed by the adaxial fusion of the edges of two lateral prophylls. The writer interprete it as follows: If the first leaf develops to envelope the inner one which is the second leaf of the first branch, the edge of the adaxial side is transformed as having a new keel at the opposite of the first keel, and overlap with another edge in the abaxial side (Fig. 5, C). Then we shall obtain the usual two-keeled prophyll derived from the first leaf with one keel. 4. The branching of Phyllostachys Type is interpreted as to be derived from the Shibataea Type which has both of monopodial and sympodial branching habit.
1. Both the zoosporangia and the paraphyses originate from the superficial cells of the sporophylls. 2. The first and the second nuclear divisions in the zoosporangium are meiosis, and then three successive mitoses take place to form 32 free nuclei. Consequently 32 haploid zoospores are produced in a zoosporangium. 3. The haploid number of chromosomes in Costaria costata is about 30. 4. The centrosomes are visible at both poles of the spindle.
In 20 among 42 samples of diatoms at Fukuwata, Shiogama, Hataori, Monzen, Furumachi, Arayu, Sumaki, Sodegasawa and Shionoyu spas in Shiobara district of Tochigi Pref., the writer found 55 taxa. Those data are as follows: New additional species to Japan: Caloneis Clevei, Cyclotella Kützingiana var. radiosa, Denticulathermalis, Fragilaria capitellata, Navicula halophila f. subcapitata, Nitzschia microcephala. New additional species to Japanese thermal flora: Achuanthes lanceolata var. elliptica, Amphiproraalata, Amphora Normanni, Cyclotella Kützingiana, Diploneis ovalis, Gomphonema parvulum var. subelliptica, Navicula contenta. N. halophila, Nitzschia vitrea. Staphanodiscus astraea, S. a. var. minutula
The so-called illegitimate dikaryotization occurs in the strain NL-55 of Collybiavelutipes. As seen in Table 1, the dikaryotization occurring in the illegitimate combination A1B1×A1B2 (homozygous for A1) is uncertain or limited in the contact zone between two mated mycelia, normal fruit-bodies being not formed at all. On the contrary, in the other illegitimate pairing A2B1×A2B2 (homozygous for A2) both dikaryotization and fruit-body formation take place as completely as in legitimate mating. In the latter case, the possibility of contamination of the adequate spores or oidia may be eliminated on the basis of the law of probability. Thus the just “intermediate” mating pattern between bipolar and tetrapolar ones results, which is called “interpolarity” in the present paper. The significance of the “interpolarity” is briefly discussed from the view-point of evolution.
Mating patterns between F1-monosporous mycelia of legitimate and illegitmateorigins in the strain NL-55 (fruit-body 55P) have been studied.The tetrapolar mating pattern as reported by Aschan (1954, p. 612) has occurredbetween legitimate F1-mycelia (Table 1). Between the other legitimate F1-mycelia(Table 2), however, the“interpolar”mating pattern as found in the parent strain55P (Takemaru 1957) has appeared again.From the pairings between illegitimate F1-mycelia, typical tetrapolar pattern hasresulted (Tables 3 and 4).These experimental results suggest, as already described by Papazian (1951), that the A incompatibility factor is controlled by at least two linked genes.