Changes with growth in the external and internal anatomy of ovary and fruit were investigated during the period from the appearance of stigmas of female flower to the harvest of fruit in Japanese chestnut. 1. When stigmas began to appear out of the central ovary of female flower covered with scales, no ovules had been formed and only locules and placentas were found in the ovary. 2. When prickles began to appear among scales and the upright styles began to spread out, meristematic tissues were observed on individual placentas, and a week later they developed into almost complete ovules composed of outer and inner integuments, nucellus and funiculus. 3. The number of locules per central ovary was 8 to 9 in‘Tanzawa’, ‘Yamato-Wase’and‘Tsukuba’, while about 10 in‘Ibuki’. The lateral ovary had one more locules than the central one regard less of cultivars. Further, each locule always had 2 ovules. 4. Late in July, when prickles developed markedly and the stigmas began to turn brown, browning occurred also in nucelli. 5. Early in August, browning occurred in nucelli of almost all ovules and in mid-August only one ovule was recognized to be growing in each ovary. Late in August, it grew rapidly downwards filling the vacant space of the locule. The other ovules died and were pressed against the ovary wall.
In order to clarify the mechanism of flower bud differentiation in Japanese pear (Pyrus serotina Rehd.), the processes of differentiation and development of the flower bud in the spur of‘Nijisseiki’pear were followed morphologically and histologically. 1. There was no increase in the number of nodes in the buds from May 30 to June 20, but thereafter, there was a rapid increase. Twelve scales were formed on June 20 and the first visible signs of flower bud differentiation were observed on June 25. 2. From June 15 to June 20 the diameter of the apical meristem in the buds expanded by one and a half times due to cell division and cell expansion. At the same time, the number of rows of cells forming the tunica was reduced, but in the corpus the number markedly increased. 3. The increase in the number of cells in the corpus led to swelling and thikening of the apical meristem from June 25 to June 30, and simultaneously the primordia of bract and floret (lateral flower) in its axil began to form in the peripheral meristem. 4. On July 10, the primordium of the inflorescence was completed and that of the sepal initiated. Thereafter, the petal primordium was initiated on July 20 and that of stamen, on July 30. From these results, it was concluded that flower bud differentiation in Japanese pear is determined by the histological changes in the apical meristem (histological differentiation) after the formation of twelve scales, particularly, by the increase in the activity of cell division in the corpus layer and by the increase in the number of nodes.
The proteins of the stem bark, stem wood and leaves of 23-year-old satsuma mandarin trees were separated into tris-soluble, alkaline-soluble and insoluble proteins. The tris-soluble proteins were separated further into five and six groups, using gel filtration and DEAE-cellulose column chromatography. Variations in the fractionated protein group were examined during spring and summer. Most of the proteins isolated, contributed to nitrogen mobilization in varying degrees. In leaves a protein of molecular weight of about 55, 000 showed the largest decrease. Amino acid analysis of six protein groups from the tris-soluble proteins of the bark showed no difference in their amino acid composition. The nitrogen storage function of proteins is discussed.
Changes in β-cyanoalanine synthase activity, rate of ethylene production, ACC and CN-content were determined in ripening and wounded fruit tissues. When fruits were examined at various ripening stages, apple fruits which had the highest rate of ethylene production, showed the greatest activity of β-cyanoalanine synthase, while satsuma mandarin peel showed the least enzyme activity. During maturation of apple fruit on the trees, β-cyanoalanine synthase activity gradually increased until November 29, then showed a marked increase. The CN- content and rate of ethylene production remained at constant levels before November 29 and increased thereafter. In wounded apple tissue, the rate of ethylene produc tion reached a peak after 24 hours, while the CN- content and β-cyanoalanine synthase activity peaked 36 hours after wounding. The rate of cyanide evolution from the cut sections of apple flesh was 2.67±0.41ng/g F.W./hr (1.71+0.26pmol/g F.W./min). Concomitant changes in the ACC and CN- content, rate of ethylene production and β-cyanoalanine synthase activity were also observed during the ripening process of fruits of Japanese persimmon and kiwifruit stored at 25°C. The development of cyanide-resistant respiration in ripening or wounded friut tissues seemed to be closely related to the increase in β-cyanoalanine synthase activity.
Experiments were carried out to analyse the cultivar differences in the composition and content of flavour compounds by applying the head space and high vacuum distillation methods. 1. Seventy to 80 compounds were detected in the gas chromatogram peaks of which 39 compounds were identified by gas chromatography-mass spectrometry. 2. The classes of the volatile compounds identified included 27 kinds of esters, 6 of alcohols, 2 of aldehydes and hydrocarbons, a phenol and an acid. 3. Esters were the most abundant flavour components detected when the head space method was applied, accounting for 80% or more of the total content of volatile compounds. And the total amounts of volatile compounds were highest in ‘Hatsuaki’(1.889ppm) followed in descending order by, ‘Kogyoku’(1.531ppm), ‘Golden Delicious’(0.196ppm), ‘Mutsu’(0.187ppm) and‘Fuji’(0.055ppm). 4. The amount and composition of volatile compounds estimated by the high vacuum distillation method were nearly the same as those by the head space method. However, in the former method the class of alcohols was quantitatively the most abundant, the percentage of total volatile compounds ranging from 53.3% in ‘Hatsuaki’to 75.5% in‘Fuji’. 5. The total amounts of volatile compounds recovered by the high vacuum distillation method were highest in the cultivar‘Kogyoku’, 9.415ppm, followed by ‘Hatsuaki’with 8.936ppm, ‘Golden Delicious’with 5.964ppm, ‘Mutsu’with 3.711 ppm and lastly‘Fuji’with 2.273ppm. 6. From the above results it can be concluded that the cultivar‘Kogyoku’and related cultivar‘Hatsuaki’contain higher levels of volatile compounds and show a higher aroma intensity than other cultivars.
The relationship between right- and left-handedness and the direction of ovary curvature in cucumber was investigated. The phyllotaxy was 2/5 with an angular divergence of 144 degrees. Plants with right- and left-handed phyllotactic spirals in the main stem were almost equally frequent. The phyllotactic spiral was reversed alternately on lateral shoots of increasing order. A cross-section of the internodes was pentagonal in shape. In the next upper internode, reversal of the configuration depended on whether the spiral of the stem was right- or left-handed. A typical female flower consisted of 5 sepals, 5 petals, 3 stigmas and 3 carpels. A cross-section of the central part of the ovary revealed 10 vascular bundles in the outer tissue (receptacle). They were connected to the central bases of the 5 sepals and 5 petals. The carpel facing the tendril was the smallest, and that on the opposite side was the largest. In most cases, the inner curve of the ovary faced towards the tendril. A high correlation was found between the right- and left-handedness and the direction of ovary curvature in cucumber.
Two experimental plots were prepared to investigate the effect of near-ultraviolet (UV) radiation on the growth and photosynthesis of turnip (Brassica cam pestris L.). They were treated by covering with UV-transmitting vinyl film (UVT) or UV-eliminating vinyl film (UVE) (Fig.1). The results were summarized as follows. 1. UV energy in UVE plot was 3 to 4% of that in UVT plot (Table 1). The temperature of UVE plot was similar to that of UVT plot throughout the growth period (Fig.2). The daily mean temperature throughout the growth period was about 19°C. 2. UVE plot was superior to UVT plot in all the characters investigated on growth (Table 2). Particularly plant length and fresh weight were significant at 5% level throughout the growth period. The growth pattern of each character was almost common to each other between the two experimental plots, except that the relative growth rate during exponential growth period of UVE plot was higher than that of UVT plot (Fig.3-1-Fig.6). 3. Apparent photosynthesis rate per unit of leaf area in UVE plot was higher than that in UVT plot at 24 days after sowing, but at 42, 48 and 70 days of after sowing the result was reversed (Fig.8). From this experiment, the effect UV on photosynthesis was not clearly observed.
To proceed with comparative physiological studies on the sexuality of Cucurbitaceae, the effect of photoperiod on sex expression of Luffa and Lagenaria plants was investigated. In Luffa cylindrica, photoperiod modified not only sex expression, but also the initiation and development of flowers, with both flower formation and pistillate flower production being greatly promoted under short-day condition. Nodes with vegetative buds, abortive staminate floral buds, normal staminate buds, mixed nodes with staminate and pistillate floral buds, and nodes with pistillate floral buds alone were formd. The increase in femaleness acropetally along the stem was similar to that of other cucurbits that also respond to photoperiod. The number of pistillate flowers increased as the photoperiod was shortened from 12h to 4h. The critical daylength for pistillate flower induction was around 12h-16h under the experimental conditions used. At least four cycles of photoinduction were required for pistillate flower production when an 8 h daylength was adopted, with more short-day cycles increasing the female tendency. There was little difference in the photoperiodic response between Luffa plants of cvs.‘Onaga’and‘Futo’. In Lagenaria siceraria, the sex expression of flowers was not significantly affected by photoperiod, although flower induction and development were affected, and flower formation was hastened under short-day conditions as in Luffa cylindrica. Since only few pistillate flowers appeared on the main stem, sex expression of these cucurbits was assumed to be similar to that of a monoecious cucumber or melon plants that produce almost no pistillate or hermaphrodite flowers on the main stem and hardly respond to photoperiod. Almost no differences in the photoperiodic responses were observed between Lagenaria siceraria var. gourda Hara(‘Oh-hyotan’) and var. microcarpa Hara (‘Sennari-hyotan’).
In order to seek fertile garlic, 31 clones were collected at the bazars of Moscow and six towns in Soviet Central Asia, and they were grown at Kagoshima. Meiosis was observed in 25 clones, which showed eight bivalents of 16 chromosomes at metaphase-I of pollen mother cells. Viable pollen grains were produced in 14 clones. Pollen-fertility varied with the clones from 90.3 to 19.6per cent. All of the clones from Alma Ata and from Frunze were fertile, though one of the five clones from Frunze developed no viable pollen but many viable seeds after pollination with other clones. On the other hand, all of the three clones from Ashkhabad and seven of the eight clones from Tashkent were sterile. The fertile clones showed several different characters as regards scape length and leaf-blade length. The fact that many fertile clones were found on the north side of the Tien Shan Mountains will be useful in discussing the primary center of garlic not yet identified, because it is presumed that garlic is evolving from fertile one to sterile one leaving some fertile clones in the primary center still now.
Elongation of the last internode of _??_ntact tulips was inhibited by dark or ancymidol treatment. More diffusible auxin was obtained from the last internode of light-than dark- or ancymidol-treated plants. GA3 application recovered the ancymidol-mediated reduction in elongation and content of diffusible auxin. Decapitation reduced elongation of the last internode. IAA recovered the reduction in elongation, but GA3 alone did not. The effect of IAA with ancymidol or with dark treatment on elongation of the last internode was less than that of IAA+GA3. It is suggested that elongation of the last internode is controlled by auxin and gibberellin, as was previously shown with the first internode.
The relationship of 5 hybrids of spring-flowering gladiolus was investigated, based on the morphological, biochemical and bibliographical data. Compared with cultivars of summar-flowering gladiolus, cultivars of spring-flowering gladiolus had smaller leaves, flowers, pollens and stomata. Those of ‘Elvira’and‘Comet’, two spring-flowering gladiolus, however, were close to cultivars of summar-flowering gladiolus in size. Starch grains in corms of ‘Robinetta’ and‘Albus’showed large, oblong figures, whereas those of the other cultivars showed small, round figures. Phenolic-like compounds were extracted from leaf tissue. Some common spots were observed between‘Comet’and‘Charm’, ‘Elvira’and‘Charm’, and ‘Robinetta’ and‘Albus’.‘Robinetta’and‘Albus’showed a poor relationship with the other cultivars. Flavonoid-like compounds were extracted from perianths.‘Elvira’, ‘Charm’and ‘Robinetta’had spots in common as had‘Elvira’and‘Comet’, or‘Robinetta’and ‘Albus’.‘Albus’showed a poor relationship with‘Comet’or‘Elvira’. In isozyme banding patterns of esterase, peroxidase and total proteins in corm tissue, ‘Elvira’, ‘Charm’and‘Comet’showed some common bands.‘Robinetta’ and‘Albus’showed very similar patterns, especially in esterase. Thus, ‘Robinetta’and‘Albus’were very similar to each other in the chemical components, and differed from the other two cultivars, ‘Comet’and‘Elvira’.‘Charm’ was between the two groups as it had some compounds in common with them. This grouping was not contradictory to the grouping based on the morphological and ecological data presented in the previous paper.
In order to obtain information on the mechanism of leakage which is often observed at the onset of plant senescence or some physiological disorders, a model experimental system has been established, which examines the kinetics and properties of betacyanin leakage from red beet discs treated with tert.-butylhydroperoxide (t-BHP). 1. No leakage of betacyanin was observed even after 4 days when red beet discs (φ13mm×1.5mm) were incubated in MES-NaOH (pH 5.8) buffer containing 0.2 M mannitol and streptomycin (0.5μg/ml) in the absence of t-BHP in the dark at 20°C. 2. In this experimental system, changing the concentration (2-10mM) of t-BHP and the duration (2-8 hours) of the treatment enabled the time when the betacyanin leakage occurred to be easily controlled. 3. As well as betacyanin, potassium ions, reducing sugars, UV-absorbing components and proteins also leaked out from red beet discs after the t-BHP treatment, but the extent of leakage appeared to be related to the molecular size. 4. The leakage showed a remarkable pH dependence between pH 5.05 and 7.43; the leakage of betacyanin occurred much faster below pH 5.8 than near pH 7. 5. Addition of calcium ion and spermine to the medium effectively prevented the leakage of betacyanin until t-BHP treatment caused leakage. Glutathione was effective only when it was used before treatment with t-BHP. Their mechanisms of prevention seem to differ. This experimental system, using red beet discs, appears to be very useful for investigating the mechanism of leakage.
Oxygen is an essential factor for the synthesis of ethylene in harvested fruit, and an almost immediate cessation of ethylene production by fruit occurs under anaerobic conditions such as 100% nitrogen. Fruits which have been prevented from producing ethylene anaerobically are able to produce ethylene when transferred to air at a rate higher than that by control fruit in air and without a lag period. In this paper, we studied whether or not fruits transferred from an environment at a low pressure or low partial pressure of oxygen to an environment at a normal pressure show ethylene production in the same manner as mentioned above. In Japanese pear and tomato fruits which are classified as climacteric in respiration during ripening, pear fruits were stored at a pressure of 190 and 285 Torr for 36 days then transferred to the ambient atmosphere after 8, 15, 22 or 36 days while tomato fruits were stored for 40 days at the same pressures then transferred to the ambient atmosphere after 40 days. The ethylene production rates of the fruits transferred from low pressure storage were measured by determining ethylene accumulation from 0 to 3 hours, 3 to 6 hours, 6 to 12 hours and 12 to 24 hours after transfer. These fruits showed higher rates than fruits which had been stored at normal pressure. However, the respiration rates of fruits transferred from low pressure storage to an ambient atmosphere were lower than those of fruits stored at normal pressure. In orange fruits whose respiration is non-climacteric, the ethylene production and respiration rates of fruits after transfer were lower than that of fruits stored at normal pressure. However, when they were stored at a high relative humidity, as high as 98% with a pressure of 190 Torr, a considerable degree of deterioration and decay occured after transfer. The ethylene and carbon dioxide production was also higher than that in fruits stored at a pressure of 190 Torr with a relative humidity of 75% or at a pressure of 760 Torr with a relative humidity of 86%.
The minimum treatment time necessary for ethylene to induce ripening (MTT) in banana fruit was examined in relation to the concentration of applied ethylene and temperature. Little difference was observed in the magnitude and rate of the climacteric between the fruits treated with ethylene only for the MTT period and those continuously exposed to ethylene. Evolution of ethylene from fruit treated with exogenous ethylene for a period less than the MTT may return to a preclimacteric level on removal to air. Applied ethylene probably induces an increase in both ethylene forming enzyme (EFE) and 1-aminocyclopropane-1-carboxylic acid (ACC) synthase activity, with EFE activity increasing first. Although the actual MTT of fruit varied considerably in different clusters, the difference in MTT for different conditions was almost constant within one cluster. The data suggest that there may be a linear relation between the MTT of bananas and the logarithm of the applied ethylene concentration, and that the effect of treatment temperature may be expressed as a quadratic function.
Changes in the content of polar lipids and in their fatty acid composition in spinach leaves during storage were studied in order to clarify the mechanism of leaf-yellowing. The total glycolipids, particularly monogalactosyldiglyceride (MGDG) and diga-lactosyldiglyceride (DGDG), decreased markedly during storage at 25°C. The total phospholipids, however, decreased moderately during storage at 25°C, the decrease in phosphatidylglycerol (PG) being the most notable. In the chloroplast lipids (MGDG, DGDG and PG), the relative amounts of hexadecatrienoic acid in MGDG, and palmitoleic acid and linolenic acid in PG decreased during storage at 25°C. Conversely, the relative amount of linoleic acid in MGDG, DGDG and PG increased. The percentage of unsaturated fatty acids in all the polar lipids, however, showed hardly any change. From these results, it is inferred that the degradation of chlorophylls may be caused by the hydroperoxides of free fatty acids which have been formed by the degradation of polar lipids such as MGDG, DGDG and PG.