With the slip of sweet potato, a “non-sensitive” plant, an electrical potential change was observed to occur at the petiole and stem following after the blazing of the leaf tip. The effect can be propagated only basipetally.
1) The distribution of phosphorylase and the starch formation from sugars in the root-tuber of the sweet-potato were histochemically investigated. 2) In the root-tuber of the sweet-potato phosphorylase was detected in all the tissues where storage starch was to be formed, such as cortex, phloem, and xylem parenchyma but it could not be demonstrated in the tissues devoid of the storage starch, such as periderm, external cortical cells and vessels, with the exception of cambium where no starch was stored. The products from Cori-ester were very small grains, resembling natural starch grains in shape and iodine coloration. They were formed solely in the cells with leucoplasts. 3) By the supply of various sugars through the cut end of the starch-free root-tuber, starch grains were formed in the cells of cortex and xylem parenchyma. Of the sugars tested, sucrose, maltose, glucose, fructose and galactose were found to cause the starch formation, while mannose and xylose were ineffective.
The branching enzyme of non-waxy maize seeds (Country Gentleman ×Wisconsin No. 690) was found to belong to the Q-enzyme type, and it differed from potato Q-enzyme producing a slightly different amylopectin. The amylopectin produced was saccharified by soybean β-amylase to 59-62% (calculated as maltose), and gave an iodine complex with a maximum at 575mμ in absorption spectrum, while potato Q-enzyme yielded an amylopectin with a limit of saccharification by β-amylase of 49% and with an absorption maximum of iodine complex at 535mμ.
The three species, N. trigonophylla, N. undulata and N. rustica were crossed reciprocally with N. tabacum. The crosses N. tabacum×N. trigonophylla, N. undulata×N. tabacum and N. tabacum (Odaruma) ×N. rustica (Afghanistan) gave some seeds, while no seeds were obtained from the three remaining crosses. No report on the hybrids N. tabacum×N. trigonophylla and N. undulata×N. tabacum or their reciprocal crosses has been published, so far as I know. In external characters the F1tabacum-trigonophylla, is somewhat smaller than N. tabacum, the leaf form is intermediate between those in the parents, and the flower colour is a pale red. F1undulata-tabacum is more similar to N. tabacum than to N. undulata, but its flowers are pale yellowish red, showing an intermediate color between the two parents. The morphology of F1tabacum-rustica agrees with that of Kostoff's description of the reciprocal hybrid (N. rustica ×N. tabacum). These three hybrids were all vigorous. All the hybrids mentioned above, showed considerable irregularities in the meiotic behaviour of the FMC's. Polysporous PMC's were often observed, and the hybrids were completely sterile. At first metaphase in F1tabacum-trigonophylla, 0-11 bivalents, mostly 5-6, were counted. In F1trigonophylla-tomentosa and F1trigonophylla-tomentosiformis, Kostoff (1941-43) observed 2-10 and 0-8 bivalents, respectively. Accordingly, the chromosome conjugation in F1tabacum-trigonophylla is assumed to be caused mostly by semihomologous chromosomes between the trigonophylla genome and the tomentosa subgenome, not the sylvestris subgenome, of N. tabacum. In F1undulata-tabacum, 0-8 bivalents, mostly 3-5, were observed. In this hybrid the number of the bivalents is a little more than that of the chromosome conjugation in haploid tabacum or F1sylvestris-tomentosiformis. Accordingly it is assumed that a few semihomologous chromosomes are present between the undulata genome and the two subgenomes of N. tabacum. In F1tabacum-rustica, 1-10 bivalents (also multivalents) were formed at the first metaphase and some secondary associations were observed at first and second metaphases. Christoff (1928) and Trenovsky (1935) also observed a small number of bivalents in F1rustica-tabacum, while Kostoff (1941-43) found many bivalents, as many as 5-24, in the same hybrid. The cause of there different results was not determined.
1. Isolated cotyledons of Vigna sinensis were cultured on nutrient medium. When a part of the hypocotyl remained at the base of the cotyledon, the former grew out in a bulge, from which adventitious roots appeared. 2. When a cotyledon was cut at the base so as to remove entirely from the hypocotyl, the cut surface was covered by callus. In such a case, adventitious roots formed from the callus. 3. When a cotyledon was cut into apical and basal halves which are nearly equal in size, the cut surface of the apical pieces produced calluses and roots, while that of the basal pieces produced neither callus nor roots though they are formed at the opposite end. 4. Anatomical studies revealed that primordium of the adventitious root was differentiated from the parenchymatous cells of the phloem in the callus at the cut end of leaf vein. 5. It was discussed that the root formation might be influenced by the supply of hormone and other materials through the vein, and also by the amount of parenchymatous cells present in the phloem. 6. The number of arcs of the adventitious roots varied from four, a normal condition of the primary root, to two, intermediate conditions occurring also frequently.