In order to clarify the process of seed abortion of prarthenocarpic Hiratanenashi persimmon, a comparative histology of the developing ovules of Hiratanenashi and Fuyu, the latter having strong seed-producing abilities, was studied.
1. The developing process of normal ovule of Hiratanenashi was very similar to that of Fuyu until bloom. Embryo-sac mother cell in Hiratanenashi was formed in nucellus portion 15-18 days before bloom. Normal embryo-sac with an egg cell, synergid cells, antipodal cells and polar nuclei was completed 2-3 days before bloom in both the cultivars.
2. Fifty% of ovules in Hiratanenashi fruits and 20% of those in Fuyu fruits were abnormal ones with undifferentiated egg cell and polar nuclei.
3. In the fertilized ovules of both the cultivars, 10 or more free nuclei appeared 6-8 days after bloom, and soon the endosperm became completely cellular. In the case of Hiratanenashi, some ovules contained in complete cellular endosperm even at the beginning of its formation, and most of them were found a little later to contain the collapsed endosperm due to the abnormal division of cells. Therefore, it seems likely that the embryo may cease the growth as a result of the degeneration of endosperm.
4. From an immature embryo of Hiratanenashi 6-10 weeks after fertilization, a single young plant-not the one redifferentiated from callus was reproduced by using tissue culture technique.
5. These findings that 1) incomplete ovules are abundantly present in this cultivar, 2) the degradation of endosperm occurs partly due to the insufficient formation of cellular endosperm and mainly due to the abnormal division of endosperm cells, would give the reasons for the seed abortion of Hiratanenashi persimmon.

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Morphological and anatomical changes of the rind cells were investigated throughout the development of satsuma mandarin fruit (Citrus unshiu MARC.). The cellulase activity of the rind tissue was also determined in relation to the cell enlargement.
1. Cell division almost ceased 20 days after full bloom in the inner layer of the albedo, 30 days in the outer albedo and 40 days in the mid flavedo, when the fruit diameters were about 10, 20 and 30mm, respectively.
2. In the albedo tissue, pectic substances began to accumulate in the intercellular spaces when cell enlargement started after the cell division had ceased. The accumulation of pectic substances increased gradualy during the development of rind. The cell wall where the pectic substances accumulated was depressed slightly toward the inside, and the primary protuberances of the cells appeared simultaneously on the portion where cells adhered closely the adjacent ones.
3. With a further expansion of epidermis, the protuberances of albedo cells were lengthened in the periclinal direction. Accordingly, the albedo cells resembled a starfish or spider in shape. In radial section of the rind, the protuberances were arranged approximately in parallel to the fruit surface. Thus, the solid albedo tissues in the younger stage were transformed to somewhat spongy tissues including large intercellular spaces. The growth of cells in the flavedo followed approximately the same process as that of the albedo. The aging of flavedo, however, was more delayed than that of albedo.
4. The water content of albedo tissue decreased since at the later stage of fruit development the intercellular spaces of albedo cells enlarged and thus the surface area exposed to the ambient atmosphere was increased. In the flavedo, however, the water content remained almost constant.
5. The cellulase activity of the albedo tissue was reduced markedly as the fruit came near the stage of maturity. On the other hand, its activity in the flavedo was reduced slightly.

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1. Satsuma mandarin fruits were examined from July to December for 3 pectic fractions obtained from the albedo and flavedo of the peel. The maximum values of the 3 pectic substances were obtained in late July or early August with subsequent gradual decrease toward harvest. The content of ammonium oxalate soluble pectic substances (ASP) remained lower than that of the other pectic substances throughout the growth period.
2. The amount of hydrochloric acid soluble pectic substances (HSP) as percentage of the total pectic substances (TP) was highest at the beginning of the growth in both albedo and flavedo, followed by ASP and then by water soluble pectic substances (WSP). The ratio of WSP to HSP, however, was reversed and such trend continued toward harvest because a rapid increase in the WSP fraction occurred immediately after the beginning of the growth. The percentage of ASP remained nearly constant throughout the growth period.
3. TP, WSP and ASP contents in the albedo were higher in the non-puffy than in the puffy fruit. HSP contents, however, were slightly lower in the former than in the latter. The calcium content of the flavedo was increased up to 1.05 per cent in late July with a subsequent decrease approaching to 0.5 per cent in early December. Although the same tendency was observed on the time course change of calcium content in both albedo and flavedo, the change was more slow-going in the former than in the latter.
4. At harvest time the variation of calcium content among cell wall fractions of the peel was greatest in lignin, followed by oxalic acid soluble pectins. In both non-puffy and puffy fruits, the calcium content was lowest in the cellulose fraction of albedo. Generally, the cell wall of the peel of non-puffy contained more calcium than that of puffy fruit peel except hemicellulose and cellulose fractions of albedo.

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The experiment was carried out to study the morphological and histochemical changes in the stem during the growth in Brassica species.
In the preceding report, the auther reported that as to the internode elongation at early stage of growth, there was no difference among all species and cultivars of Brassica used for studies but they were classified into four types after fourth leaf stage of growth: namely, 1). rosette type stem, 2). C-genome type stem, 3). Nigra type stem and 4). long vegetative growth type stem.
In this experiment, histochemical changes in the process of internode elongation of the four types of Brassica species were studies as to monosaccharides, polysaccharides, nucleic acid and lignins respectively.
The results were as follows: The elongation of hypocotyl occurred during the early stage from 4 to 6 th leaf stage, afterwards it stopped and lignification of the cell wall occurred in the four types. No essential difference was observed in histological observation, although morphological differences were recognized in four types of the internode elongation.
With all histochemical techniques used in this study, no difference was observed in these four types of internode elongation. The internode elongation and scape elongation were compared with histological and histochemically.
In despite of much differences in the rate of their internode elongation, no histological and histochemical differences were observed between the internode tissues and scape tissues in all varieties.
From these results, some discussion was made as to the internode elongation and scape elongation.

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Relationship between fruit weight and seed content within and among varieties in the tomato fruit was studied by two variety tests in order to clarify how environmental condition or tomato breeding influences on the relationship between these two characters.
Within-variety correlation and within-variety regression between the two characters were about 0.60 and 0.95 in the average of variety and experiment, respectively, but the within-variety correlations and regressions showed considerably large. variations among varieties near to the significant level. From these results it was inferred that on the whole there was positive correlation between fruit weight and seed content within variety, and hence environmental conditions positively affected the two characters and caused the increase of one accompanied with that of the other. Furthermore, it was also inferred that there was varietal difference, namely, genotypic difference among the degrees of the association expressed by correlation and the directions of the association expressed by regression.
Subsequently, phenotypic, genotypic and environmental correlation were estimated from the analyses of variance and covariance in order to examine the relationship between the two characters among varieties. From the phenotypic correlations it was also confirmed that environmental conditions could produce positive correlation between thee two characters. On the other hand, genotypic correlation was about 0.60 in the average of experiment. The genotypic correlations were considered to be statistically significant. This suggests that the direct improvement of fruit weight by tomato breeding has been accompanied with the indirect increase of seed content and various types of varieties have been differentiated, some developing heavy fruits with fewer seeds, while others producing plenty of seeds in smaller fruits.
High heritability values were obtained in both the characters.

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Muskmelon plants were planted in soils adjusted at 2 pH levels- 6.90 (high) and 5.42 (low), at 2 organic matter levels- added (high) and not added (low), and with 2 kinds of steam sterilization- steamed and not steamed. The water soluble and exchan geable Mn in the soils was markedly increased by steaming and with lowering soil pH, and was distinctly reflected in the toxicity symptoms, the Mn in plant tissue, and the plant and fruit growth. The available Mn in the soil was less affected in the high pH by steaming, but it was markedly increased in the low pH by the treatment. The water soluble Mn was decreased by adding organic matter. This probably is due to the formation of a chelate complex which combines divalent Mn with organic constituents.

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The present studies were carried out in order to establish the method of clonal propagation by leaf tissue culture in Phalaenopsis and Vanda.
1. Tissues cultured were the leaf segments of dimensions 8-10×8-10mm excised from young seedlings and matured plants of the both orchids, as well as the leaf tip of 5-7mm in length from infant seedlings of Vanda and the whole leaf of 8-10mm in length from those of Phalaenopsis.
The tissues were cultured under light on agar media containing various components, and the subsequent formation of protocorm-like bodies (P.L.B.) on the explants was observed.
The first external sign of cellular activity in explants was the appearance of a tiny protuberance to the tissue. The protuberance was seemed to be a primordium of P.L.B.
2. It was observed that the young leaf tissue from infant seedlings of Phalaenopsis and Vanda formed the P.L.B. easily by aseptic culture. In that, the P.L.B. were formed on the adaxial surface just above the basal cut-end of the explant in 2Vanda and on the surface of adaxial side in Phalaenopsis.
3. In both orchids, the proximal tissue of a leaf formed the P.L.B. more easily than the distal one.
4. The ability of the P.L.B. formation was high in the explant of infant seedlings, though a low ability was observed when the explant was excised from a seedling advanced in age. The lowering of the ability with aging of seedling was shown more clearly in Vanda than in Phalaenopsis.
5. The reduced ability of the P.L.B. formation in the eyplant from matured plants of Phalaenopsis can be tolerably recovered by means of etiolation of stock plant. The tissue from an unexpanded distal part of the etiolated leaf formed primordia of the P.L.B. fairly well. The primordia may develop into the P.L.B. after culturing in succession.
6. The result of the morphological observation shows that the P.L.B. formed on explants may be derived from epidermal cell (or cells) or cells just below epidermis.
7. As a practical medium for the P.L.B. formation, the following recipe will be recommended.
Hyponex (N:P:K=7:6:19) 3.5g
myo-Inositol 100.0mg
Nicotinic acid 1.0mg
Thiamine•HCl 1.0mg
NAA 5.0mg
Kinetin 10.0mg
Sucrose (Including the sucrose contained in fruit juice) 3.0%
Fresh strained apple juice (or coconut milk) 100.0ml
Distilled water 900.0ml
pH was adjusted to approx. 5.3
8. The P.L.B. formed on the explants of both Phalaenopsis and Vanda was shown to grow to juvenile plants on a medium suitable for the seed germination of the orchids.

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The author intended to examine the effect of cooling of bulbs, forcing temperature and gibberellin treatment on the growth and flowering of iris ‘Wedgwood’.
The number of days to flowering differed little between the plants from bulbs cooled at 13°C for 40 days and those cooled at 8°C for 40 days. The number of leaves, height of plant and length of flower stalk at the flowering time increased in the plants cooled at 13°C than those cooled at 8°C. When the bulbs were cooled at 13°C for 28, 35, 42 or 49 days and were grown at 18°C, the number of days to flowering and the height of plant decreased as the cooling period was prolonged.
In order to examine the effect of forcing temperature on the growth and flowering, the following two series of experiments were designed; (1) bulbs cooled at 13°C for 45 days were planted at 15°C, 20°C and 25°C on September 30, and (2) bulbs cooled at 13°C for 20 days were planted at 13°C, 18°C, 23°C and 30°C on June 15. None of the plants forced at 25°C in Exp. 1 and 30°C in Exp. 2 flowered at all and the flower buds blasted. The plants forced at the temperatures below 23°C flowered, though the flowering percentage was lower at higher temperatures. The number of days to flowering decreased remarkably and the height of plant increased and the length of flower stalk decreased as forcing temperature was raised. When the plants grown at 30°C for 5 or 10 days were shifted to 18°C, they did not blast and flowered with nearly the same percentage as plants forced continuously at 18°C.
When the bulbs were soaked with gibberellin solution of 100 or 500mg/l and stored at 20°C without cooling, their flower bud initiation and development were accelerated. Although the flower bud formation was equally accelerated by gibberellin application and cooling treatment, the number of leaves increased in the bulbs treated with gibberellin and decreased in the cooled bulbs. When the bulbs were dipped in gibberellin solution of 100mg/l for 20 hours after cooling at 8°C for 45 days, the number of days to flowering decreased by 13.6 days with a slight increase in flowering percentage, comparing with those given cooling treatment only. The length of leaves and flower stalk increased by gibberellin treatment.

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The author intended to examine the effect of light intensity and stored supply of bulbs on the growth and flowering of iris ‘Wedgwood’.
When the light intensity during the forcing period was limited to even 28 percent of the sunlight at noon of fine days in November at Shinshu University, Ina district (29, 000lux), all the plants grown from 25-30g bulbs which had been cooled at 8°C for 45 days flowered. With smaller bulbs and/or with a shorter cooling period, the percentage of flowering decreased under the limited sunlight intensity.
When plants were defoliated 1, 2, 3 or 6 leaves, the percentage of flowering decreased scarcely in the plants with 1 and 2 leaves defoliated, and decreased slightly in those with 3 and 6 leaves defoliated, comparing with intact plants. There was no difference in the number of days to flowering among them. The length of flower stalk and the weight of the top rather increased in the plants with 1, 2 and 3 leaves defoliated as compared with those in intact plants. On the other hand, the weight of newly formed bulblets decreased in the defoliated plants as compared with intact plants and the greater number of leaves defoliated, the smaller the weight of newly formed bulblets.
In order to examine the effect of scales of bulbs on flowering, bulbs of 25-30g cooled at 8°C for 45 days were planted with their scales removed. The flowering percentage of these plants decreased to about a half of that of intact plants, and also the length of flower stalk decreased though the number of days to flowering hardly differed from that of the intact plants.
In the plants grown from bulbs of various weights, the flowering percentage and number of days to flowering were little different between the plants grown from 25-30g bulbs and those from 15-20g bulbs, both obtained from the same district in Japan. On the other hand, there were remarkable differences in the percentage of flower- ing, number of days to flowering and height of plant, among the plants grown from bulbs of the same weight but obtained from warm, cool and cold climate districts in Japan.
Dry weight of plants and the contents of starch, total sugar and nitrogen in mother bulbs were examined during growth with the plants grown from the bulbs treated with low temperature and gibberellin, with low temperature only and without any treatment but stored at 20°C before planting, respectively. These examinations revealed that dry weight and the contents of starch, total sugar and nitrogen decreased rapidly in those treated only with low temperature, decreased more rapidly in those treated with low temperature and gibberellin, and decreased slowly in those without any treatment but stored at 20°C until planting, respectively. On the other hand, dry weight and the contents of the substances in the top increased rapidly in the plants grown from bulbs treated with low temperature and gibberellin, and increased slowly in those grown from bulbs without any treatment. In the plants grown from bulbs treated with low temperature and gibberellin and those treated with low temperature only, the time of flowering concurredd with the time of exhaustion of the storage substances in mother bulbs to be empty.
From the results obtained above, it may be concluded that the materials for flowering of iris ‘Wedgwood’ are provided mainly by the mother bulb, not from photosynthesis during the growing period, when the size of mother bulb is relatively large enough and the top growth is supported by smooth supply of storage substances from mother bulb. These considerations suggest, therefore, that iris ‘Wedgwood’ may scarcely produce blasting flowers, even if the light intensity was relatively low during the growing period of the plant in, Japan.

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The sensory test was conducted by the ranking test or Scheffé test to, determine the relationship between viscosity of the juice and sensory rating for daintiness of satsuma mandarin (Citrus Unshiu MARC.) fruits and to examine whether viscosity of the juice suited for the indices of eating quality of the fruits or not.
In the case of the ranking test, the difference in daintiness among the fruits used to this test was recognized by some estimated values on Spearman rank correlation, Kendall coefficient of concordance and Kramer sum of ranking score.
A number of panel was fond of the fruits having high viscosity of the juice. The liking orders of panels for daintiness of the fruits (subjective ranking) agreed well with the orders of viscosity of the juice (objective ranking).
On the other hand, the difference in daintiness among the fruits was determined by the difference in viscosity of the juice in Scheffé test as well as the ranking test and the more difference in viscosity of the juice was a large value, the more difference in daintiness of the fruits was a large degree. If the difference in viscosity of the juice was a small value, there was no difference in eating quality between the fruits. In this test, the subjective ranking corresponded with the objective ranking.
As mentioned above, the viscosity of juice was considered a good index of eating quality of citrus fruits.

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Effects of ethylene on the respiration and ripening of fruits were observed. The critical concentration of ethylene in the respiration of satsuma mandarin, natsudaidai, and tomato fruits was considered less than 1ppm.
The treatment with 1ppm ethylene was much effective on promoting the ripening of mature green tomato fruits, but it was little on immature fruits (18th day after anthesis). These seemed to suggest that the critical concentration of ethylene might change at some ripening stages of fruits.
The effects of. ethylene on the respiration and ripening of fruits increased little in 100 and 1000ppm in comparison with 10ppm, indicating that 10ppm was enough to promote the ripening of fruits.
Treating with 10ppm ethylene for 3 days or more, the respiratory peak of satsuma mandarin and natsudaidai fruits appeared on either 2nd or 3rd day since starting the treatment, and after that the respiration decreased in spite of keeping up the treatment.
In mature green tomato fruits, the climacteric rise of the respiration appeared soon after the treatment, and it continued to rise to its peak after stopping the treatment.
When Japanese persimmon fruits were treated 10ppm ethylene during 3 days or more, the respiratory peak appeared either 3rd or 4th day since starting the treatment, and the flesh of the fruits had softened at the peak.
The treatment with ethylene increased a bit of soluble solids content in the fruits of non-astringent type (var. Fuyü); on the contrary, decreased it much in the fruits of astringent type (var. Hiratanenashi).
On the one hand, in the treatment with 10ppm ethylene during a single day the flesh softening got slow in speed than that during 3 days or more. On the other hand, the treatment with 10ppm ethylene for more than 3 days was not considered to be so much effective on the respiration and ripening of fruits than that for 3 days.

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To study the postharvest physiology of white peaches, “Okubo” and “Hakuho” peaches were held at 10°C, 15°C, 20°C, 25°Cand 30°C, respectively. Respiration, ethylene evolution, firmness, readiness of peeling, sugars, edible quality and other components of ripening were determined during ripening.
1. A more rapid increase and a higher peak in ethylene evolution, an earlier peak in respiration and a more rapid attaining of readiness of peeling were observed in “Okubo” peaches ripened at 20°C than in those ripened at 25°C, whereas softening proceeded at 20°Cas rapidly as at 25°C. A few days after the respiratory climacteric peak, “Okubo” peaches ripened at 20°Cand 25°C showed a peak in ethylene evolution, followed by a rapid decline. At the respiratory climacteric peak, “Okubo” peaches were fully ripe at 20°Cand over-ripe at 25°C.
2. Higher rates of ethylene evolution on the first day after harvest and a more rapid rate of softening were observed in “Hakuho” peaches than in “Okubo” peaches. An earlier peak in respiration and a more rapid rate of softening were observed in “Hakuho” peaches ripened at 25°C than in those ripened at 20°C, whereas ethylene evolution increased at 25°C as rapidly as at 20°C.
3. Gradual increases in respiration and ethylene evolution and delayed softening and attaining of readiness of peeling were observed in peaches ripened at 10°C and 15°C. “Okubo” peaches ripened at 10°C and 15°C attained about the same rates of ethylene evolution and the same degrees of softening and peeling as those ripened at 25°C, while poor flavor developed at 10°C. The rates of ethylene evolution at 15°C remained relatively constant for a long period after the respiratory climacteric peak, as compared with those at 25°C. Full ripening required about three times at 10°C and two times at 15°C as much time as at 25°C.
4. Ethylene evolution was suppressed and tended to decrease during ripening at 30°C. Although the respiratory climacteric failed to develope at 30°C, softening proceeded in “Hakuho” peaches as rapidly as at 25°C and it proceeded in “Okubo” peaches at a slightly slower rate than at 25°C for a few days after harvest and subsequently at approximately the same rate.
5. The reducing sugar content increased gradually at 30°C during ripening. The increase in soluble pectin content seemed to be significantly related to the degree of softening.
6. These data suggest the following. The ripening temperature influenced flesh color, rates of ethylene evolution and softening, and certain other ripening phenomena. Ethylene stimulated an occurrence of a respiration climacteric and other ripening reactions such as softening and readiness of peeling. Respiration, ethylene evolution, softening, readiness of peeling and other ripening reactions proceeded relating to each other during ripening, but these interrelations were influenced by factors such as variety and ripening temperature.

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