The present experiment was undertaken to confirm the generally recognized assumption concerning the chimerism of Kobayashi-mikan. This cultivar is supposed to be a synthetic chimera which has arisen from the junction of satsuma mandarin (Citrus unshiu Marc.) scion and Natsudaidai (C. natsudaidai Hayata) stock. Peroxidase and esterase isozymes of foliage and fruit parts as well as immature leaves and rootlets of young seedlings were analyzed by starch gel electrophoresis. The results obtained from a zymographic comparison of Kobayashi-mikan, satsuma mandarin and Natsudaidai are summarized as follows. 1. In the case of samples taken in July, peroxidase isozyme patterns of new and old leaves as well as albedo of Kobayashi-mikan distinctly resembled those of Natsudaidai. The pattern of juice sac of Kobayashi-mikan considerably resembled that of satsuma mandarin. Esterase isozyme patterns of flavedo and albedo of Kobayashi-mikan were completely the same as those of Natsudaidai. 2. In the case of samples taken in October, peroxidase isozyme patterns of old leaves as well as flavedo of Kobayashi-mikan were nearly the same as those of Natsudaidai. The patterns of albedo and new leaves of Kobayashi-mikan resembled those of Natsudaidai. Esterase isozyme patterns of old leaves and seeds of Kobayashi -mikan were equal to those of Natsudaidai. The patterns of flavedo, alvedo and new leaves of Kobayashi-mikan were rather similar to those of Natsudaidai. 3. Peroxidase and esterase isozyme patterns of immature leaves and rootlets of young seedlings grown from seeds of Kobayashi-mikan were similar to those of young seedlings grown from seeds of Natsudaidai. From these results, the hypothesis that Kobayashi-mikan is a graft-induced periclinal chimera between satsuma mandarin and Natsudaidai has been further confirmed.
During the coloring of normal puffy cultivars of satsuma mandarin (Citrus unshiu Marc.), the peel (flavedo plus albedo) continued to grow, i.e. increase its fresh weight, even after the pulp growth had terminated. The fruit became puffy when the pulp growth had already ceased but the peel was still growing. This peel growth accompanied the increase in dry weight, and the soluble sugar accounted for almost all of the dry matter increase in the peel. While, the content of alcohol insoluble substance remained unchanged. Protein content and acid phosphatase activity in the peel increased gradually during the coloring. Ethephon enhanced the puffiness to some extent and slightly increased peel fresh and dry weights. During coloring, the peel growth and the increase in sugar content of‘Imamura unshu’, which is known as a non-puffy cultivar, were slower than those of ‘Sugiyama unshu’, a normal puffy cultivar.
The purpose of this study was to clarify the effects of ethylene on peel puffing of satsuma mandarin (Citrus unshiu Marc.) cv. Sugiyama fruits. 1. Ethylene evolution from fruit was greatly increased by spraying fruit on the tree with 100ppm ethephon on Oct. 28. The occurrence of peel puffing was enhanced and specific gravity was significantly lower in the ethephon-treated fruit than non treated fruit. 2. Fruit on the tree were treated with 10-4M of aminoethoxy analog of rhizobitoxine (AAR) by 10sec. dipping on Nov. 26 and Dec. 1 and 4. By this AAR treatment, ethylene production of fruit was suppressed, the occurrence of peel puffing was depressed and the decrease of specific gravity was delayed. 3. When fruits harvested on Dec. 1 were stored at 20°C in 12l containers with ethylene absorbent (KMnO4) until Dec. 22, ethylene concentration in the containers was lowered and the occurrence of peel puffing was depressed as compared with when stored with ethylene absorbent. 4. AAR and KMnO4, which depressed the occurrence of peel puffing, decreased the ratio of peel weight to fruit weight, and the content of water soluble pectin while increased the content of 0.4% sodium hexametaphosphate and 0.05N hydrochloric acid soluble pectins as compared with their respective controls. The reverse was true for ethephon, which enhanced peel puffing.
Intergeneric crossing between Japanese pear Pyrus serotina Rehd. var. culta Rehd., and quince, Cydonia oblonga Mill., was made in 1972. From 60 Japanese pear flowers pollinated with quince pollen, 23 fruits were set and 97 fertile seeds were obtained from them. When the seeds were planted in a greenhouse in the next spring, 47 seedlings were obtained with a germination percentage of 48.5. Among them, only 7 seedlings survive to the present time while the others of the seedlings died off at the young stages. One of 7 seedlings (No. PQ-5) flowered in the spring of 1983, and proved to be an intergeneric hybrid from the analysis of peroxidase isozymes. Morphological characteristics of this hybrid are as follows. Young leaf: Much pubescent on young leaves and upper part of current shoot. Ligh yellowish-green, slightly tinged with brown. Adult leaf: Ovate in shape with acute apex, truncate base and serrulate margin. Smooth on the backside. Petiole length intermediate between the parents. Flower: White in color, 5_??_7 petals per flower and 1_??_3 flowers per cluster. Many pollen sterile.
The cellular breakdown in watercore tissue of the Japanese pear was investigated by identifying the change in cell wall polysaccharides and their constituent monosaccharides, and by tracing cell wall-degrading enzyme activity. The activity of xylanase and arabanase, which degrade hemicellulose components, increased more watercore tissue than in healthy tissue during the initial stage of the disorder (grade 1-2), but a rise in activity was not observed during the severe stages (grade 3-4 and 5-6). The activity of the other hemicellulases (β-xylosidase, β-glucosidase and β-galactosidase) showed little difference between healthy and damaged tissue. On the other hand, increases in the neutral form of endocellulase activity at grade 1-2 and in polygalacturonase activity at all grades were prominent in the watercore tissue, as observed in a previous paper(5). In the watercore tissue, the breakdown of the cellulose component was the most prominent among all of the cell wall polysaccharide components. That is, the cellulose component had already begun to decrease at grade 1-2, and was further reduced at the more severe stage of the disorder to about 85% and 75% of the cellulose in healthy tissue at grade 3-4 and 5-6, respectively. Acid soluble-hemicellulose components also decreased at grade 3-4 and 5-6. However, there were no differences in the alkali-soluble hemicellulose components between healthy and damaged tissues. This tendency resembled the cell wall degradation pattern observed in over-ripe fruit. Thus, the watercore in the Japanese pear seems to arise from the fact that some parts of the fleshy tissue ripen faster than other parts.
Anatomical studies were made on root initiation process of the cuttings of a wild peach which is native of Shimoina district, Nagano Prefecture and known to be resistant to root-knot nematode, for the purpose of obtaining fundamental informations on mass production of peach rootstocks. Histochemical observation onthe activity of succinic dehydrogenase was also conducted. No root primordia were present in stem tissues at the time cutting was made. Rooting was stimulated by the treatment with 25ppm indole butyric acid (IBA) in both of softwood cutting under mist and hardwood cutting with bottom hert (aver. temp.;20.4°C). When IBA-treated, root initials arose in secondary phloem parenchyma cells external to the cambium 5 days after planting on both of softwood and hardwood cuttings, and each of them developed into an organized group of cells, namely a root primordium 10-14 days and 7-11 days after planting on the former and the latter, respectively. Root primordia before protrusion showed a highest succinic dehydrogenase activity in apical meristem and procambial strands. Subsequently, vascular connections developed between young roots and stem vascular systems. Young rootselongated at a right angle to the main axis of stem on softwood cuttings, while perpendicularly on hardwood ones. No root primordia were recognized in IBA-untreated cuttings. The first protrusion of root was observed 17 days after planting on softwood cuttings and 13 days after on hardwood ones. Protrusion of root on softwood cuttings was recognized not only at the cut surface of the basal stem end but also at the part just above it. Hardwood cuttings formed callus vigorously at the basal stem end and rooted exclusively at the cut surface. Differences in the continuity of sclerenchyma between softwood and hardwood cuttings proved not to be related to their different rooting potentials.
The amounts of the surface wax and its major component, the hard wax, of ‘Delaware’grapes increased rapidly until 30 days after full bloom and made little change thereafter to the harvest time. On the contrary, the soft wax kept almost a constant level in the early stage of berry growth and increased steadily in the late stage. Further, with the advance of berry growth, a distinct change occurred in the composition of long-chain alcohols, the main components of the soft wax. These seasonal trends in the hard and soft waxes were similarly observed in both gibberellic acid (GA)-treated (seedless) and untreated (seeded) berries. The accumulation of surface wax was inhibited in‘Delaware’when the postbloom GA application was late for the recommended time, 10 days after full bloom. The amount of the surface wax was compared at maturity among 5 leading cultivars in Japan.‘Delaware’, regardless of GA treatment, was highest in the amount of total and hard waxes, followed by‘Muscat Bailey A’, ‘Campbell Early’, ‘Kyoho’and‘Muscat of Alexandria’, in this order. In the amount of soft wax, however, ‘Campbell Early’was highest, followed by‘Kyoho’, GA-treated‘Delaware’, ‘Muscat of Bailey A’, GA-untreated‘Delaware’and‘Muscat of Alexandria’, in this order.
The changes in L-phenylalanine ammonia-lyase (PAL) activity were investigated during berry ripening in relation to the coloration of 3 grape cultivars;‘Muscat of Alexandria’(white grapes), ‘Kyoho’(purple grapes) and‘Super Hamburg’(black grapes). In all cultivars, higher PAL activity in the skin was observed at the earlier stages of berry development, followed by a rapid decline toward veraison to a considerably lower level. In‘Kyoho’and‘Super Hamburg’, PAL activities gradually increased again with the beginning of berry coloration.‘Super Hamburg’had more anthocyanin content and higher PAL activity than‘Kyoho’. The sugar content in the skin rose rapidly in the ripening period in all cultivars, preceding the increases in both PAL activity and anthocyanin content in‘Kyoho’ and‘Super Hamburg’grapes. Free-abscisic acid (ABA), also, rapidly accumulated in the early stages of ripening in each cultivar and maintained a considerably higher level. However, there was no much difference in the maximum ABA content among 3 cultivars.
The effect of application of the mixture of acetylene and water on the induction of flowering in pineapples varies greatly from day to day. This variation seems to be related to the diffusion of acetylene affected by air temperature and wind velocity. To overcome the situation we developed a method using oil-coated calcium carbide which would slowly release acetylene when coming in contact with water. Oil-coated calcium carbide was prepared as follows. Three hundred thirty grams of soybean oil was heated to 220_??_250°C, and 1kg of calcium carbide (1_??_3mm in diameter) was poured into it and mixed for 10_??_15 minutes, keeping the temperature at 220_??_250°C. Then, the mixture was exposed to the air for 40_??_60 minutes for oxidative polymerization. When 50ml of water was poured on 1g of the oil-coated calcium carbide in 1min, the carbide was separated from the oil and began to evolve acetylene gas about 1h after. The evolution of acetylene continued for 8h. While, the uncoated carbide evolved acetylene only in 2min. The application of the oil-coated carbide at 1g per plant induced flowers in pineapples at higher rates with less daily fluctuation of its effect than that of the mixture of acetylene and water in both cool and hot season, although they were comparatively less effective in the latter.
Muskmelons (Cucumis melo L.) were grown in diluted sea water from transplanting to harvest in order to determine the salt tolerance at 3 growth stages-stage I (transplanting to pollination), stage II (pollination to fruit net development) and stage III (fruit net development to harvest). Treatment solutions contained 0, 250, 500, 750 and 1, 000ppm Cl in sand and soil cultures, and 0, 1, 000, 2, 000, 3, 000 and 4, 000ppm Cl in nutrient solution culture. Whole plant dry weight and fruit fresh weight at harvest decreased with increasing sea water concentrations in all cultures. The increment in growth at stages II and III was less at higher sea water concentrations. Growth was reduced more in sand than in soil culture. Slightly visible salt injury symptoms appeared at stages II and III at 1, 000ppm Cl in sand culture and at the beginning of stage I at 3, 000 and 4, 000ppm Cl in solution culture. Cl and Na increased, while SO4 and osmotic potential decreased in leaves at the end of stage III in all cultures as sea water concentrations increased. Cl and Na in leaves tended to be higher in sand than in soil culture at all stages. Cl was especially high at stage I. More accumulation of Cl and/or Na in leaves at stage I in sand than in soil culture may be one of the causes for greater growth suppression in sand culture.
Freezing resistance of the genus Rhododendron of about 70 species or cultivars was assessed. In very hardy rhododendrons, the difference in hardiness between florets and other tissues or organs became greater: The vegetative buds, leaves and stem cortex were hardiest, while the florets which survived freezing by extraorgan freezing were the least hardy. Even in the hardiest rhododendrons, the flower buds did not survive freezing below -35°C, while the vegetative buds, leaves and stem cortex survived even -60°C. It is notable that very hardy rhododendrons, except for the dwarf forms, such as R. brachycarpum, R. catawbience and R. maximum, all belong to the Ponticum Series of the genus Rhododendron. And most of very hardy cultivars belong to R. catawbience hybrids. The flower buds of rhododendrons found near the timber line (3, 900m in altitude) of the East Himalayan mountains were marginally hardy at -20 to -23°C. Nearly the same results were obtained from the Yunnan′s rhododendrons. These are less hardy than those found in the subalpine forests of Japan and eastern North America. Thus, in the Himalayas and Northeastern Yunnan, rhododendrons seem not to have evolved species capable of resisting below -30°C, probably due to moderate temperatures and high humidity in winter in these areas.
An experiment was conducted to determine the effect of macro- and micro-elements, and boron (B) on growth, keeping quality and leaf marginal burn in chrysanthemum (Chrysanthemum morifolium Ramat. cv. Seikonohana). Thirty day old cuttings were planted in wooden containers (40×40×12cm) filled with sand, and grown in a greenhouse, under normal photoperiodic conditions. Four plants were grown in each container. There were 6 treatments consisting of 2 levels of macro- and micro-elements and 3 levels of B at 0.5, 1.0 and 1.5ppm as shown in Table 2. Treatments were replicated 4 times. Treatment solutions were applied to the sand medium from July 11 to flowering (approximately 0.5 liters/container/time), twice on clear days, once on cloudy days and none on rainy days. Plant height decreased in the treatments receiving high macro-elements. Fresh weight of cut flowers decreased in the treatments with low macro-elements + high B. When macro-elements or B were high, dry weight of roots decreased. Keeping quality of cut flowers decreased by 18 to 22 days in the high B treatments compared with the treatment with the treatment with low macro- and micro-elements and low B. Flowering date was not affected by any treatments. Marginal burns on the lower leaves of the plant in the treatment with low macro-elements and high B appeared in late August and those in the treatment with high macro-elements and high B or with medium B did in early September. Thereafter, these symptoms developed towards upper leaves. Marginal burn was highly correlated with B content in the leaves. B was slightly higher in the lower leaves.
The present study was undertaken to make clear the effects of plant density on the growth and quality of cut flowers in early-forced tulips. The cultivars used were‘Cassini’and‘Apeldoorn’in 1979 and‘Cassini’, ‘Trance’and‘Apeldoorn’in 1980. 1. The solar radiation in the plant community increased with decreasing plant densities. However, the effect of solar radiation on the areal weight, one of the determinants of cut flower quality, was not clearly recognized. 2. The dry matter production at the high plant density was larger at the early and middle growth stages but smaller at the late stage as compared with those at the control and low plant densities in‘Cassini’. While, in‘Apeldoorn’, it was larger only at the early growth stage and become smaller thereafter than those at the control and low plant densities. 3. The values of LAI increased with increasing plant densities and it was especially true of‘Cassini’. They were nearly proportional to the values of plant density (number of bulbs per unit area) in‘Cassini’ but not in‘Apeldoorn’. 4. The values of CGR also increased with increasing plant densities almost throughout the forcing period and it was especially ture of‘Cassini’. In‘Apeldoorn’, however, they increased slowly till the middle growth stage and increased rapidly thereafter. 5. In‘Apeldoorn’, the quality of cut flowers lowered with increasing plant densities, while in‘Cassini’ and‘Trance’ it was not affected by plant density. The ratio of dry weight of flower to that of a whole plant did not differ with plant density regardless of cultivars. However, the ratios of dry weight of stem and leaves to that of a whole plant increased and decreased, respectively, with increasing plant densities. 6. These results suggest that‘Cassini’and‘Trance’ can be forced at plant densities higher than usual without lowering flower quality, while for‘Apeldoorn’ plant densities higher than usual are not desirable.
In Sanbokan fruit, chemical compositions of the granulated juice sacs in the stem-end region of segment and the gelated and granulated sacs in the middle region of segment were investigated. Some microscopical observations were also made on these juice sacs. By the microscopical observations, we found that the epidermis of the granulated juice sacs were extremely thicker than that of the healthy sacs in the stem-end region of segment, but, in the middle region of segment, it was slightly thicker than that of the healthy sacs. Cell wall polysaccharide contents of the epidermis and inner parenchyma were suggested to be higher in the granulated sacs than the healthy sacs by staining with PAS. Pulp and alcohol-insoluble solid (AIS) contents were higher in the granulated juice sacs than the healthy sacs. Cell wall polysaccharide content was also higher in the gelated and granulated sacs, and it was especially true for hot water, hemicellulose and cellulose fractions. In the stem-end region of segment, free acids, flavonoids, carotenoids and RNA were lower, while bound acids, vitamin C, total-N, AIS-N and amino-N were higher in the granulated sacs than the healthy sacs. Total sugars differed little between them. In the middle region of segment, all the chemical components measured were lower in the gelated sacs than the healthy sacs. In the granulated sacs, however, AIS-N and amino-N were higher than in the gelated and healthy sacs, and total sugars, bound acids, flavonoids, carotenoids, vitamin C and total-N were higher than in the gelated sacs but lower than in the healthy sacs. RNA was almost the same as, and free acids were lower than in the gelated sacs. In the stem-end region of segment, mineral components (crude ash, Ca, Mg, K, Na) were all higher in the granulated juice sacs than the healthy sacs. In the middle region of segment, they tended to be slightly lower in the gelated sacs than the healthy sacs. In the granulated sacs, Ca was higher, while K was lower than in the gelated sacs. On the basis of these results, we discussed the development of gelation and granulation in juice sacs of Sanbokan fruit.
Ripening changes in respiration rates, ethylene emanation, flesh firmness and color development of plum (Prunus salicina Lindl.) fruits were investigated using 3 cultivars of‘Ooishi Wase’, ‘Beauty’and‘Santa Rosa’. The fruits were picked 2_??_6 times at different stages of maturity and stored at 20°C. Respiration rate on the tree, which was estimated by measuring the CO2 output of the fruit 24 hours after harvest, showed a climacteric pattern in all of the 3 cultivars. In early maturing cultivars (‘Ooishi Wase’and‘Beauty’), the rise of respiration rate occurred earlier and progressed more rapidly than that of late maturing cultivar (‘Santa Rosa’). The changes in respiration rate during 20°C storage were different with the stages at harvest in all of the 3 cultivars. That is, there were no respiratory climactric rise nor rise in ethylene emanation, unless the fruits were harvested at and after climacteric minimum on the tree. In‘Ooishi Wase’and‘Beauty’, the climacteric rise advanced rapidly with red color development and softening of flesh, while in‘Santa Rosa’, the climacteric rise and softening of flesh advanced much more slowly than color development. The free abscisic acid content of attached fruits increased with the rise in respiration rate during ripening on the tree. That of detached fruits also increased even when the fruit was harvested earlier and showed no climacteric rise during storage. The fruits treated with 500ppm ethylene for 48 hours after harvest did not induce a respiratory climacteric, an ethylene rise nor hastening of ripening, unless they were harvested at and after climacteric minimum.
Effect of storage temperature and humidity on the function of mitochondria prepared from cucumber fruits was investigated in relation to the occurrence of chilling injury, The cucumber fruits were packaged in perforated polyethylene bag (dry condition) and non-perforated but not-sealed polyethylene bag (humid condition) and stored at 1, 6 and 15°C, respectively. Pitting, a symptom of chilling injury, was observed at 1°C after 2 days in perforated bag and after 4 weeks in non-perforated bag, while it did not occur at 6 and 15°C in both packages. Carbon dioxide evolution from the fruits showed a trend to be higher in non-Perforated package than in perforated one throughout the storage at 1 and 6°C. A marked increase of CO2 evolution was found when the fruits were transferred from 1°C to 15°C, in the same manner in both packages. The rate of succinate-oxidation of mitochondria prepared from 1°C stored-fruits decreased with advance of storage period, whereas it increased gradually or kept the same level as that prepared from 6 and 15°C stored-fruits. The rate was higher in the fruits in non-perforated bag at every temperature. Respiratory control ratio (RCR) of mitochondria was about 1.6 at the beginning of storage. During the storage at 1°C it rapidly decreased and became about 1.0 after 4 days, indicating disappearance of respiratory control ability. At 6 and 15°C, it decreased reaching to 1.3, but kept the value after that. These trends were similar between the 2 packages regardless of temperature. The change in ADP/O ratio was also similar between both packages, and it decreased rapidly at 1°C, in contrast to an increase at 6 and 15°C. The reduction of RCR at 1°C was reversible within a week of storage, and was restored when the fruits were transferred to 15°C. From the results mentioned above, it may be concluded that early occurrence of pitting injury was found under dry condition such as in perforated package at 1°C, while the lowering of mitochondrial function would be induced immediately by low temperature storage at 1°C, irrespective of packaging style or storage humidity.