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Male-sterile plants were obtained from a variety of the onion, Senshu-Hiragata-Ohtamanegi (a strain Yellow Glove Danvers), in 1944 and 1948. The pollen degeneration of the male-sterile plants was investigated cytologically in 1949 and 1950. The flower buds and anthers of the normal and the male-sterile plants were fixed in CARNOY's fluid. The usual methods of dehydrating and embedding in paraffin were employed. The sections were cut 10μ thick and stained with HEIDENHAIN's iron-alum haematoxylin. The results obtained may be summarized as follows:
1. The maturation divisions of P.M.C's in the male-sterile plants were normal up to the liberation of microspores from tetrads, but the nuclear divisions of microspores were not observed.
2. The cells of the anther tapetum began to behave in an abnormal manner, from late tetrad stage to the liberation of microspores (fig. 3). The boundaries of the tapetal cells broke down, and the contents flowed together to form a periplasmodium (fig. 4).
3. After the periplasmodium has attained maximum development, it began to degenerate (fig. 5). With the complete disintegration of the periplasmodium the microspores were finally destroyed. The anther cavity became empty, except for a dark strand of disintegrating microspores (fig. 6).

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This exp eriment was carried out to find the method, in which some special phenomena accompanied with the aging of seed potatoes could easily be seen in the laboratory. As a result, it was proved that the stage of aging was determined by the state of sprouting, when examined in the dark.
The principal phenomena attracted the authors' attentions were the decrease of sprout growth, the death of apical part of sprout, and the tuberization at the end of sprout in early stage. The abnormalities, however, recoverd regularly by the treatment with a synthetic phytohormone, α-naphthaleneacetic acid, so that it may be supposed they occurred by the decrease of growth substance accompanied with the progress of aging.
In addition, the increase of sprouting, the loss of polarity, which had commonly been known as a sign of aged, became visible in a comparatively short period under the condition of darkness. Therefore, it may be very effective to determine the aging of seed potatoes to apply the method of examination in the dark above mentioned.

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(1) In order to make the physiological constitution of the pithy tissue in root crops clear, the author investigated the process of the occurrence of pithy tissue in company with the corpulent growth in root by using radishes.
(2) As to the occurrence of pithy tissue in the radishes grown corpulent to a certain degree, it was first observed the disappearance of sugar in the large types of cells of xylem parenchyma which were far apart from the conducting tissue, and then among the neighbouring cells producing intercellular space lysigenously and schizogenously it gradually expanded till to assume the shape of pithy tissue.
(3) When the content of soluble matter in the roots was examined at the central part, the circumferential part and the middle part of both, it was ascertained that parenchyma in the middle part in which pithy tissue occurred, was less of its content in comparison with that in the other parts, and on the whole the more the degree of pithy tissue in he crops was, the more the content in them was lowered.
(4) Pithy tissue occurred when the length of leaves, the number of leaves, the weight of roots, the diameter of them and so on increased rapidly while the rate of T/R decreased, and during this period the cells of parenchyma reached to the maximum in size and number, and the content of the soluble matter indicated the minimum.
(5) Ones which have a great deal of pithy tissue can be found generally among those heavy in weight and wide in diameter, but among which the rate of T/R is greater the occurernce is less.
(6) The first step to the occurence of pithy tissue will be ascribed to decrepitude of the cells of parenchyma, and it will be concluded that mainly due to the rapid growth of the cells the content of the matter falls, and in addition to that by bringing out the difficulty in supply of nutrition from the conducting tissue it causes a sort of the starving condition.

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“Ebi”disease of grape vine is characterized by poor setting of berries, chlorotic condition of leaves and poor seed development in berries. Though this disease has been known on vineyards in Yamanashi Prefecture for many years, its causes have not been fully elucidated. Experiments were carried out in border to clarify the effect of boric acid sprays applied before blooming upon the own-rooted Kosyu sanjaku grapevines suffering from the“Ebi”disease.
The results were as follows;
1. Sprayings of 0.3% boric acid solution on the leaf, flower cluster, or both, a week and three weeks before blooming decreased abnomal flowers, improved setting of berries, and increased the average weight of fruit clusters more than double the untreated ones.
2. Germination of pollon grains was improved by the treatment.
3. Average number of seeds per berry and percentage of abnormal seed were increased by the treatment.
4. Development of vascular strands in peduncle (fruit stalk) was greatly promoted, but leaf mottling was not corrected, and growth of young canes had not been accelerated by the treatment.
5. In this experiment, significant correlation was not found between percentage of setting of berries and percentage of abnormal flowers, severity of leaf mottling, or length growth of young canes.
6. It seems that boric acid may be absorbed through the leaf surfaces and the flower cluster, and improved pollon activity, fertilization and meristematic activity of the flower stalks.

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1. The mother plants of edible burdock for seed growing should be selected from the plants grown up to a certain size, as the small ones have little flowering probabilities.
2. The plot sown in June 5th shows the best flowering possibility, while many non-flowering plants are seen in earlier and later sowing.
3. There are two types of the plants at flowering time, i, e, the dwarf and the tall. Majority of larger plants becomes to the dwarf type and smaller ones to the tall type. Further investigations are required to answer the question whether this is due to physiological factors or genetical one.
4. In Kyushu edible burdock blooms during July, and flowers opened before July 20th brings good seeds. Later blooming ones might bring a bad result due to high temperature.
5. The tall type plants have better set percentage and produce better seeds in quality than the dwarf type.

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Tetraploid non-branching stocks which were induced by colchicine treatment usually produce a small number of double flowering plants in addition to the greater part of single ones, so that they are not suitable yet for economical growing to get cut-flowers. Besides, the tetraploid double flowering spikes are rather short, harder and later growing than diploids, although each florets is somewhat larger and possessed of numerous thicker petals. As doubiness of florets in normal diploid stocks is presumed to be arised from a monogenic recessive factor, namely, the double flowering plant is“ss”and the single one“Ss”, the original tetraploid single flowering plant is manifested with“SSss”and they produce numerous single flowering progenies included with three genic types, SSSs, SSss and Ssss, added with a few double flowering ssss-plants.
SSSs-typed plants have somewhat narrow and deep-greenish colored linear leaves, slowly growing habit and produce only single flowering plants. SSss-plants have the same habit as an original mother plant with wide leaves slightly serrated and bring forth only a few (2-16) percentage of double flowering plants in the next generation. Ssss-plants grow occasionally fast with fairly serrated wide leaves and are endowed with many“semi-double”florets which are formed with a few defective surplus petals, and, furthermore, they bear some times a smaller quantity of seeds than SSss-plants and give 23 to 28 percentage of double flowering plants in the next generation. Full double flowering ssss-plants which are completely sterile due to lacking in stamens and pistils are easily distinguished from single flowering by their strongly serrated larger ruffled leaves which are so brittle and much light-greenish colored. And here is a noticeable occurrence, that is, occasional appearance of the full double flowering plants in the progenies of Ssss or SSss-typed parents. They have the same deep-greenish colored and fairly serrated leaves and stout stems as sirlgle flowering Ssss-plants. These abnormal plants are possibly endowed with Ssss-factors but produce full double florets without stamens and pistils caused by unstable overwhelming of three recessive factors sss against one dominant S.
In order to raise percentage of double flowering plants in tetraploids (at least above 25%), Ssss-typed plants only should be ensured for seed production by morphological selection as mentioned above, because, on the contrary, SSss and SSSs-plants are usually superior in number in mass growing and are acting on lowering percentage of double flowering plants (less than 5%). The author expected theoretically, it would be easy to get fifty percent double flowering strains of triploid stocks which would be induced by crossing Ssss-typed tetraploid and Ss-diploid. However, so far as his experience concerned for three years, triploid seeds were hardly produced by the above crossing. Only two seeds were obtained in 1999 from 540 flowers cross-pollinated and they grew up well to a double flowering and a single flowering triploid plants. It will be worthy to note, however, that this triploid single F₁ plants obtained by crossing between a diploid branching purple-red and a tetraploid non-branching pink has produced many good F₂ seeds which are almost of the lavender-flowered tetraploid structure, and then each plant of F₂ or F₃ progenies are now becoming an initial of a new branching or non-branching tetraploid strain having white, pink, lavender or purple-colored flowers respectively. Although tetraploid stock strains are inferior to diploids in regard to get cut-flowers as stated before, they will be much useful and even precious for people who want to make researches in plant genetics.

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1. Some experimental researches on the ground water bearing upon the root development of fruit trees were carried out by the present authors in 1949 and 1950.
2. The level of the ground water in an orchard which was surrounded with the paddy field varied with the condition of irrigated water in paddy field.
3. Grape was resistant to the underground stayed water, Mituba- and Maruba-Kaido (apple stocks) was medium and persimmon was weak. Red-clover and hairy-vetch (leguminous green manure) was seemingly resistant to the underground stayed water, but potato was very weak.
4. A distinct difference in the growth of top and root was observed between the plot of lower ground water and that of higher. The high level of ground water limited not only the length of roots but also the growth of top, especially in the case of subsoil to 20cm.

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[in Japanese]

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[in Japanese]

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