1. The physiological characteristics of satsuma mandarin trees having flowers with or without leaves make an interesting object for study. 2. Six 15-year-old satsuma mandarin trees growing at Fujieda in the citrus region of Shizuoka, were selected for their uniformity in size and other general conditions. 3. It might be assumed that the production of flowers is a reaction to the supply of elaborated food material in the tree and that the tree responds by putting forth leafy and/or leafless flowers, corresponding to the vigour of vegetative growth. 4. The figures given in Table 1 show the percentage distribution of fruit branches according to length, diameter at the base and volume. A survey of this Table shows longer and larger branches present on oblique and vertical framework branches. There is evidently a tendency for the vertical framework branches to produce stronger fruit branches. 5. The figures given in Table 2 show flower production on fruit branches of different lengths for vertical, oblique and horizontal framework branches. In order to place the number of flowers produced on the fruit branches of different lengths on a comparable basis, the results are expressed per 10cm length or per 1cm3 volume of each fruit branch. Many more flowers are produced on short fruit branches growing from horizontal framework branches. There is evidently a tendency for fruit branches of poor growth to produce far more flowers per 10cm length and per 1cm3 volume. 6. The figures given in Table 3 show that both leafy and leafless flowers are produced most profusely on short fruit branches present on the horizontal framework branches, and this is particularly true of leafless flowers. 7. The figures given in Table 4 show that the leafless type is produced more abundantly on fruit branches present on the horizontal framework branches and less on fruit branches present on the vertical framework branches. The leafy type is produced more abundantly on fruit branches present on the vertical framework branches, the opposite of the situation for the leafless type. 8. It is shown in Table 6 and Fig. 6 that the development of the leafless flowers is inferior to that of the leafy flowers in size and weight. The leafless flowers, present on fruit branches of poor growth, are inferior in the nutritional competition and tend to cease growth and abscise earlier in the season.
1. The present paper deals with the preliminary efforts to produce seedless fruits in Hyuganatsu and Hassaku using crosses of 2X×4X, a procedure which results in the formation of abortive seeds in many cases. 2. Two hundred flowers of Hyuganatsu (Citrus tamurana Hort. ex TANAKA) were emasculated and pollinated with pollen grains of the 4X Natsudaidai (Citrus natsudaidai HAYATA). The fruits thus obtained were normal in size, weight and skin color, but almost all the seeds degenerated into rudiments and traces at an early stage of development. They were virtually seedless. 3. The soluble solid and titrable acid contents in the juice of the ripe seedless fruits showed no difference from the control. The edible portion of these fruits increased by 15% as compared with the control. 4. The seedless fruits did not differ from the controls by date of dropping early or late. Also they displayed similar pattern of development of dry juice sacs after freezing in the winter. The fruits after harvest were stored in a carton box under room condition for about two months. They did not display any particular change in the contents of the soluble solids and titrable acids in the juice during storage. The seedless fruits seemed to soften a little faster than that of the control fruits. 5. The flowers of the Hassaku (Citrus hassaku HAYATA) were pollinated with pollen grains of the 4X Natsudaidai. The fruits thus obtained were virtually seedless and did not differ from the control in fruit growth and size or in other qualities. The results coincided with those for the Hyuganatsu×4X Natsudaidai cross. 6. Further investigations are under way for the purpose of finding the proper proportion of the 4X Natsudaidai tree to be planted as a pollinizer for Hyuganatsu.
In an electron microscopic study of the stigma of the unpollinated satsuma man darin flowers, it was revealed that the top surface of the stigma consisted histologically of papillary cells of various sizes and the underlying parenchymatous tissues. The surface of these papillary cells was covered with mucilaginous excretions. Cell walls of papillae were coated with cuticular layers which stretched inwards to a site just before the junction of the papillary and underlying parenchymatous cells. Excretion of mucilaginous substances was effected by sporadic destruction and extinction of cuticular layers where some electron dense granules were formed. In these zones, a gradual transition was observed from degenerated electron dense granules to the frothy structure of mucilaginous excretions. This fact indicates that some substances deriving from decomposed membranous material were fused to granular bodies and further released into the ambient spaces through each breakage of cuticular layers. In the papillary cells, marked swelling occurred on the sporadically rough-surfaced inner cell wall where the Golgi apparatus and several Golgi complex-derived vesicles seemed to function as active producers of cellulosic substances. Juvenile papillary cells were uninuclear and the nucleus was surrounded by chromoplasts containing several starch grains each. Some other organelles such as Golgi apparatus, mitochondria, ribosomes, vesicles, vacuoles, osmiophilic granules, rough-surfaced endoplasmic reticula, etc., were observed in the protoplast of papillary cells. Protoplasts of adjacent cells were connected with each other at their basal portions by the plasmodesmal strands.
1. In order to elucidate the mechanism of gall formation caused by the root-knot nematode (Meloidogyne incognita var. acrita), an egg mass of the nematode was inoculated on the second internode of the balsam plant (Impatiens balsamina), and changes in respiration rate, carbohydrate contents and incorporation rate of assimilate were observed during gall swelling. 2. Oxygen absorption and CO2 evolution in the gall tissues slightly increased one week after inoculation and no further increases were observed until 7 weeks after inoculation when they increased markedly. Eight weeks after inoculation they became 2.5 and 3 times greater, respectively, than those in the normal tissues which had been fairly constant during the whole period of swelling. 3. The carbohydrates found in the normal and gall tissues were starch, glucose, fructose, sucrose, oxalic acid, malic acid, citric acid and iso-citric acid. In general, starch, oxalic acid, citric acid and iso-citric acid contents were higher in the gall tissues. Malic acid content in the gall tissues between 3 and 7 weeks after inoculation and reducing sugar content in the gall tissues between 1 and 5 weeks after inoculation were higher than those in the normal tissues. There was no marked difference of the sucrose content between in the normal and gall tissues. 4. Every 14C-activity incorporated into the sugar, organic acid and amino acid fractions of the gall tissues was 6 times greater than those in the normal tissues.
Changes in concentrations of endogenous hormones during berry development were investigated in relation to the ripening of Delaware grapes. The concentration of ethylene was low before and during ripening. Gibberellin and cytokinin activities were high in the early stage, but then declined to lower levels before initiation of ripening. The concentration of IAA in seedless berries was high before veraison, then decreased rapidly, while that in seeded ones decreased gradually from 3 weeks after anthesis to veraison. The time of disappearance of absorbed 2, 4-D in the 2, 4-D treated berries coincided closely with the time of initiation of ripening. ABA contents of seeded, seedless and 2, 4-D treated berries increased remarkably as they ripened. The data indicate that an auxin-ABA relationship may be involved in the natural regulation of grape ripening.
Polyembryonic satsuma mandarin (Citrus unshiu Marc.) was crosspollinated with trifoliate orange (Poncirus trifoliata L.). Embryos were isolated from immature seeds 90, 120, and 140 days after pollination. Isolated embryos were divided into the following five stages: Stage I: Globular-shaped embryo (less than 0.1mm in dia.) Stage II: Early heart-shaped embryo (0.1mm-0.3mm in dia.) Stage III: Middle _??_ (0.3mm-0.4mm _??_) Stage IV: Late _??_ (0.4mm-0.5mm _??_) Stage V: Torpedo-shaped embryo (greater than 0.5mm in dia.) These embryos were cultured on Murashige and Skoog (MS) medium and MS medium supplemented with 20% non-autoclaved cucumber juice (C. J.) under aseptic conditions. The growth of embryos and the number of differentiated cotyledons were greater when 90 and 120 day embryos except Stage V were cultured on the medium with cucumber juice whereas no such effects were observed on 140 day embryos. On the contrary, root differentiation and rooting were reduced by the addition of cucumber juice. These findings indicate that there would be two factors or complexes present in cucumber juice; (1) a factor causing both growth and differentiation of cotyledon, (2) a factor causing inhibition of root growth. For the successful rearing of heart-shaped embryos isolated 90 and 120 days after pollination, it appears that the following series of subcultures at one month intervals would be recommended: (1) Initial culture of heart-shaped embryos on MS medium with 20% C. J. and 3% sucrose. (2) Subculture of those embryos on MS medium with 3% sucrose without C. J. (3) Subculture of them on MS medium with 1.5% sucrose. (4) Transplanting young seedlings to vermiculite. Zygotic seedlings with trifoliate leaves obtained were about 40 to 60% of total seeds examined and such seedlings came only from embroys in Stage IV and V.
From late autumn to early summer, seasonal changes in leaf water potential, leaf diffusion resistance and the growth of two current shoot and trunk were examined in satsuma mandarin (Citrus unshiu MARC.) trees in well watered soil. 1. Leaf water potential before sunrise (ψmax) became lower than -3 bars from mid-November when the soil temperature fell below 12°C and leaf diffusion resistance increased sharply. This indicates that the water metabolism of satsuma mandarin trees became increasingly inactive from mid-November. ψmax was lowest between January and February, and reached around -3 bars in mid-April when the soil temperature surpassed 11°C. Thereafter, leaf water potential during the daytime (ψmin) remained stable in the range of -4 to -5 bars until early in June (during the summer, ψmax and ψmin show about -3 bars and -10 to -13 bars, respectively, under wet soil conditions). 2. Leaf diffusion resistance began to decrease sharply from late March, but average resistance was approximately 30sec/cm in mid-April when ψmax reached about -3 bars. Near recovery of leaf diffusion resistance to summer level (4 to 8 sec/cm) did not occur until June. On the other hand, diffusion resistance of juvenile leaves whose length attained 3 to 5cm showed around 15sec/cm and reached values similar to the summer level in eary June. 3. Sprouting was observed in early April when ψmax reached about -4 bars. During the period of sprouting and blossom opening, the diameter of shoot and trunk decreased slightly. This suggests that energies for sprouting and flowering depend mainly upon the reserve nutrients in a tree.
Muskmelon plants were grown in sand culture and fertilized with a complete nutrient solution containing 0.5, 30 and 60ppm Mn, and 1.33, 4.00 and 12.00mM Ca; 30 and 60ppm Mn, and 1, 30 and 60ppm Fe, in addition to control, 0.5ppm Mn and 1ppm Fe. In the experiment of Mn and Ca: Mn in the plant parts was significantly increased as Mn concentrations were raised from 0.5 to 60ppm, while inversely decreased as Ca concentrations were raised from 1.33 to 12.00mM. The fresh weight, soluble solids and scores of external fruit appearance were significantly decreased with increasing Mn levels, and were not improved with increasing Ca levels. No fruits with cracking at the blossom-end were found at 0.5 and 30ppm Mn regardless of Ca levels, while they were found at 60ppm Mn with 1.33 and 4.00mM Ca. In the experiment of Mn and Fe: Mn in the plant was significantly increased with increasing Mn levels, while inversely decreased with increasing Fe levels. The fresh weight, soluble solids and scores of external appearance of the fruits decreased at 60ppm Mn, and those receiving 30ppm Mn were significantly decreased with increasing Fe levels. No cracked fruits were found at 30ppm Mn, while they were found at 60ppm Mn regardless of Fe levels.
When cotyledons of radish plants were excised at an early stage of growth, decrease in plant growth was observed. To understand this phenomenon, the role of cotyledons in radish growth was examined. Dry weight of cotyledons decreased and that of the other organs increased in the dark, whereas dry weight of every organ increased in the light. Furthermore, dry weight of hypocotyls and that of roots decreased in decotylized plants grown in the light, but decrease in dry weight of foliage leaves was not observed. From these results, it was concluded that cotyledons were the source and the other organs were the sink. Especially, the foliage leaves could be regarded as the strongest sink. In Rapid Red cultivar, the growth phase could be divided into two periods (Phase 1 and Phase 2). In Phase 1, the growth of foliage leaves was enhanced by the supply of reserve materials and photosynthetic products from cotyledons. In Phase 2, activet hickening growth of hypocotyls was caused by a sufficient supply of photosynthetic products from foliage leaves. Therefore, it is concluded that the decrease in radish growth by decotylization is due to the resulting decrease in the growth of foliage leaves.
An investigation was made to determine the effects of nitrogen forms, and pH in soils having low and high levels of Mn on the growth and flowering of carnation cv.‘Yosooi’. Treatments were arranged factorially involving Iwata and Kawazu soils, NH4-N from (NH4)2SO4, and NO3-N from NaNO3, at high and low pH levels. The number of flowering plants, plant height, and top fresh weight decreased in the Kawazu soil having a high level of Mn. The time of flowering was markedly promoted by NH4-N. The number of flowering plants, and the top fresh weight decreased at the low pH. In the later stage of growth tip burn symptoms were found on leaves of plants grown in the Kawazu soil at the low pH. The Mn in the various parts of plants grown in the Kawazu soil was markedly increased at the low pH, but was not affected by the N forms. The content of N, P and K, and the Fe/Mn in the leaves were slightly higher in the Iwata soil, while the Mg and Al were high in the Kawazu soil. At the low pH the Al in the leaves increased, while the P, K and Ca, and the Fe/Mn decreased. At the termination of the experiment the water soluble, exchangeable and easily reducible Mn increased in the Kawazu soil. The available Mn increased at the low pH, while the easily reducible Mn decreased. The various forms of Mn in the soil were not affected by the N forms. The Na, Ca, Mg and Al increased in the Kawazu soil at the termination of the experiment, while the P decreased. The NH4-N increased in the NH4-N treatment, while the NO3-N and Na decreased. The K and Al, and the value of EC increased at the low pH, while the NO3-N, P, Na and Ca decreased. From these results, the growth retardation and tip burn symptoms of carnation seemed to be highly correlated with the Mn in the plants and soils, and disassociated with the P, K, Mg and Al in the leaves, and the NH4-N, NO3-N, Na, Mg, P and Al in the soils.
In order to clarify the use of Gibberellin (GA) in cut flower and pot plant production of Lilium speciosum rubrum. and the role of the GA′s in shoot emergence and elonga ion; flower differentiation and development, these experiments were devised to study: 1. The response to exogenous GA′s. 2. The levels of endogenous GA-like substances. 3. GA-synthesis or GA-reactions to the inhibitor Ancymidol and their interaction. The following results were obtained: 1. Endogenous GA-like substances in bulbs decreased dramatically during 60 days of cold storage at 5°C, which is most effective in breaking dormancy and hastening stem emergence, elongation and flowering of L. speciosum rubrum. In contrast, GA-like substances increased during 60 days at 21°C. This 21°C temperature is ineffective in breaking dormancy and hastening shoot emergence and flowering. GA was more effective than CCC and Ancymidol to break dormancy as a bulb soak. These data show that it is not clear what the exact role of GA′s are in stem emergence. 2. There was an interaction between shoot elongation and the changes in the endogenous GA-like substances found in the shoot. Shoot elongation was markedly inhibited by Ancymidol, with decreased levels of endogenous GA along with shoot inhibition which was reversed by GA. Such data indicate the important role of GA in shoot elongation. 3. Flower differentiation was not inhibited by high concentrations of Ancymidol. Further, application of GA3 or GA4+7 did not induce flower differentiation of stems from noncooled bulbs. It was concluded that GA was not directly involved in flower differentiation of L. speciosum rubrum. 4. Flower development was strongly inhibited by Ancymidol and this reaction was reversed by GA. There was a direct reaction between the rate of flower development and the fluctuation of endogenous GA′s. We concluded that GA had an important role in flower development of L. speciosum rubrum.
This paper reports the effects of several inhibitors of protein and RNA synthesis on the respiration of banana peels stimulated by ethylene. As for method of addition of inhibitors to the banana peels, dip-infiltration was better than vacuum-infiltration, because vacuum-infiltration had severe effects on tissue and respiration was stimulated by ethylene produced by the stress of the infiltration. Actinomycin D did not inhibit respiration of the tissue. Cycloheximide almost eliminated the peaks of induced respiration by ethylene treatment. But this inhibitor rapidly stimulated carbon dioxide production, so it seems that cycloheximide affected not only protein synthesis but respiration directly. Basic respiration before treatment of ethylene, was slightly reduced by D-threo-chloramphenicol, but the stimulated respiration by applied ethylene overcame the action of this inhibitor. Puromycin decreased the incorporation rate of L-Valine-U-14C into protein from 90 to 60% at 12, 24, 48, and 72 hours after the start of ethylene treatment. In spite of this inhibition of amino acid incorporation, this inhibitor did not reduce the respiration rate after ethylene treatment. There were no changes of total free amino acid and protein contents in peel tissue while respiration was stimulated with added ethylene. These data suggest that the stimulation of respiration by ethylene may not be associated with de novo protein synthesis.
This paper reports the effects of harvesting season and maturation of eggplant fruit on pitting injury and browing of seeds and pulp during low-temperature storage. Pitting injury was less frequent on unripe fruit (5-7 days old after flowering) and overripe fruit (24-27 days after flowering), and pitting injury was more frequent at the proper harvesting stage (14 days after flowering). On the other hand, the younger the fruit was, the more frequent the browning of seeds and pulp was during low-temperature storage. Pitting injury decreased during the late harvesting season, but the browning of seeds and pulp did not decrease. In contrast fruit stored at 20°C did not display pitting injury and the browning of seeds and pulp during storage at any season. The unripe fruit contained higher levels of polyphenols than fruit harvested at the proper stage or overripe fruit. Three days old fruit contained 344mg/100g f. wt of total phenols and the polyphenols content decreased with advance of the maturation of the fruit. For example, 13 days old fruit contained 55mg/100g f. wt of total phenols. The fruit at all stages contained a 30-40% o-diphenol fraction of total phenols. The main o-diphenol of eggplant fruit pulp was identified as chlorogenic acid by paper chromatography. As this polyphenol was fairly oxidised by the crude enzyme extracted from eggplant fruit pulp and its reaction mixture browned, it seemed to be the substrate of browning during storge. Total phenols content and o-diphenols content of unripe fruit rapidly increased before the browning of pulp and decreased as the browning of the pulp browned during low-temperature storage. On the other hand, total phenols content and o-diphenol content of overripe fruit which did not show the browning of pulp was almost constant during low-temperature storage. The activity of polyhenol oxidase increased rapidly before the browning of pulp and decreased after the browning of pulp during low-temperature storage, while the activity of polyphenol oxidase increased gradually in the unripe fruit stored at 20°C and the overripe fruit.
It is important to study the physiological response of fruit to limited levels of vibration in order to facilitate decisions with regard to grading and transporting fruits and vegetables. Effect of vibration at 1G, 2G and 3G for various periods from 30 minutes to 5 hours on the respiration rate of tomato fruit was determined. The respiration rate of tomato fruit increased rapidly from the beginning of vibration for every vibrating condition. The increase continued throughout vibration, and remained at an elevated level for a few hours after vibration. This high respiration rate fell once slightly followed by a small rise again, and then returned gradually after 10 hours or more to the initial state. An increase of respiration rate proportional to the vibration time was observed for each vibrating acceleration level. At the same vibration time, the increase of respiration rate was proportional to the intensity of vibrating acceleration, when the vibration time was short. But, for the longer vibration time, a higher respiration rate at the low vibrating acceleration was observed. The increase of respiration rate at 3G of vibrating acceleration was lower than that at 1G or 2G. The vibration effect on the respiration rate of tomato seemed to be sensitive in the fruit at turning stage of ripeness, and therefore, after-ripening might be disturbed to some extent. From the results obtained above, it was clear that a sensitive response occurred physiologically in tomato fruit under vibrating conditions not sufficient to produce direct injury, and that after the vibration was terminated, the effects on respiration continued for a certain period. Moreover, it may be that some physiological disorder would be produced by intensive vibrating acceleration.