(1) Temporary falls of the resting potential (maximum c.a. 100mV) observed in the seed embryo of Vigna sesquipedalis are supposed to belong to the category of the general excitation phenomenon, because they can be brought about by stimuli of various nature in the some manner, although their processes are some 103-104 times as slow as those in animal tissues. (2) Applying rectangluar current pulses (1-60V) on the hypocotyl of the plant by means of two accessed stimulating electrodes, the presence of a polarity in parallel with the growth axis was confirmed concerning the excitability; fairly distinguishable two types of the electric responses (I & II) were detected, each corresponding to the positive (acropetal) and negative (basipetal) direction of the stimulating current applied. In this case one of the measuring electrodes (M+) was placed in the middle of the two stimulating electrodes and another one (M0) on the boundary of hypocotyl and radicle as counter electrode. (3) A double propagation of excitation with velocity of 0.2-0.5mm per minute along the growth axis was also observed. (4) Quantitative relations between intensity as well as length of stimulus and excitation were investigated. Excitation of the type I takes place complying with the Weber-Fechner's low, while that of the type II has its maximum at a certain strength of stimuli. (5) Further expriments, where M+ was placed on the same position as either of the stimulating electrodes, proved the existence of one more polarity in the radial direction of hypocotyl, namely, out flux of the stimulating current from the surface of the organ causes the excitation of the type I while influx of the stimulating current causes the excitation of the type II, irrespective of the direction of current along the growth axis. (6) Thus the polarity along the growth axis reveals itself in the deviation of the “neutral point” towards root tip concerning the excitation types. The nature of the radial polarity was discussed on the basis of the movement of ions through stressed protoplasmic membranes.
1) The karyotype analysis of mosses, eight species belonging to three genera, was carried out: Entodon Challengeri _??_ K(n)=11=V(H)+V+8(6v+2j)+m(h) E. chloroticus* _??_ K(n)=11=V(H)+V+8(6v+2j)+m(h) E. ramulosus _??_, _??__ K(n)=11=V(H)+V+8(6v+2j)+m(h) Brachythecium populeum _??_ K(n)=10=V(H)+3V+5(4v+j)+m(h) B. decurrentifolium* _??_, _??_ K(n)=10=V(H)+2V+6(4v+2j)+m(h) B. Buchanani var. japonicum* _??_ K(n)=10=V(H)+2V+6(4v+2j)+m(h) Hylocomium cavifolium _??_, _??_ K(n)=6=V(H)+2V+2J+m(h) H. proliferum* (sterile) K(n)=12=2V(H)+4V+2J+m+m(h) 2) By three dioecios species, i.e. Entodon ramulosus, Brachythecium decurrentifolium, Hylocomium cavifolium, the chromosomes and the heteropycnosis in prophase nuclei of both male and female gametophytes were carefully compaired with one another, but no sex chromosomes differed in morphology have been fouud 3) The chromosome numbers in the genus Hylocomium studied in this paper show a polyploid series of n=6, 12. The diploid species H. proliferum has two sets of chromosome complement which is approximately similar in the morphology of chromosomes to that of the monoploid species H. cavifolium.
1. In the present report, the results of cytogenetical studies of 2 F2 plants (TimoSaF2) of T. Timopheevi×S. africanum F1 were described. 2. The number of somatic chromosomes of the 2 individuals was found to be 39 (TimoSaF2-1) and 25 (TimoSaF2-2) respectively. 3. External characters of the TimoSaF2 plant were quite different from those of F1 as shown in the Table 1 and Photo. 1. 4. The number of bivalents in one PMC at heterotypic metaphase varied 5-14 in the TimoSaF2-1 and 3-9 in the TimoSaF2-2. The frequency of bivalents in the PMC's of the F2 planes was tabulated in the Tables 2 and 3; occurrence of 9II (TimoSaE2-1) and 6II (TimoSaF2-2) appeared to be the mode respectively. 5. The 2 individuals of TimoSaF2 plant were completely sterile.
1. This paper deals with the results of the research on the characteristics and type of pairing of chromosomes in the reduction division in P.M.C. of the F1-hybrid which is raised artificially by crossing Rubus hirsutns Thunb. (_??_) and R. trifidus Thunb. (_??_). 2. The seeds obtained in the cross are easily germinated. The growth of the F1-hybrid is well. 3. The types and frequency of the pairing of the chromosomes in the metaphase of first division in the hybrid P.M.C. are as follows: 7II... 30%, 6II+2I ... 39%, 5II+4I ... 29%, 4II+6I and 3II+8I ... less than 1%. 4. The 93% of pollen of this hybrid is empty and the rest is full in content. The seeds of this hybrid are sterile. 5. This hybrid does asexual propagation vigorously. The larger size of the flowers and more numerous in florescence of the hybrid as compared with those of the parents indicate that it shows heterosis.