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Volume 75, Issue 5
Displaying 1-10 of 10 articles from this issue
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ORIGINAL ARTICLE (ENGLISH)
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Fumio Fukuda, Ryuji Yoshimura, Hiromi Matsuoka, Akiko Umeda, Yoshimi A ...2006 Volume 75 Issue 5 Pages 365-371
Published: 2006
Released on J-STAGE: September 25, 2006
JOURNAL FREE ACCESSWe investigated the morphology of seed, particularly of the endosperm of intact and abscising ‘Shimizu Hakuto’ peach (Prunus persica Batsch) subjected to different fruit thinning levels for four years. The objective was to study the anatomical basis for physiological fruit drop which occurs from end of Stage 2 to beginning of Stage 3 of fruit growth. The percentage of physiological fruit drop was significantly higher (P = 0.05) in trees subjected to heavy fruit thinning (HFT) than in those subjected to light fruit thinning (LFT) or standard fruit thinning (SFT). The mean endosperm length in fruit which dropped at the peak of physiological fruit drop from trees under HFT was equal to that of intact fruit collected at 65 days after full bloom (DAFB); the mean embryo length in dropped fruit was shorter than that in the intact fruit collected at the same time. Endosperm and embryo cells in dropped fruit showed typical necrotic symptoms, such as cells with shrunken cytoplasm and collapsing cell nucleus. Collapsing cell nucleus in the endosperm of the intact fruit collected from trees under HFT began at 66 DAFB that corresponded with the time when the endosperm stopped growing. Morphology of chalazal haustorium was observed in the on-tree fruit collected from the beginning to the middle of Growth Stage 2 in trees under HFT and SFT. Although most chalazal haustoria had reached the chalaza at the beginning of Growth Stage 2 in both fruit thinning levels, those in most of HFT fruit exhibited abnormal shrinking at 54 DAFB. These results indicate that a series of events take place in the seeds predestined to drop. That is, after certain factor(s) that cause shrinking of the chalazal haustorium and retardation of embryo growth to occur, assimilated reserves in the endosperm cannot be translocated to the embryo because of shrinkage of the chalazal haustorium. Finally, necrosis of embryo is induced.
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Masashi Yamamoto, Tatsuya Kubo, Shigeto Tominaga2006 Volume 75 Issue 5 Pages 372-378
Published: 2006
Released on J-STAGE: September 25, 2006
JOURNAL FREE ACCESSSelf-incompatibility and compatibility of 65 citrus accessions were determined by pollen tube growth in the style. Lemon was self-compatible whereas the six pummelos and seven out of 11 its relatives were self-incompatible. Furthermore, among sour oranges and their relatives, two out of six accessions were, likewise, self-incompatible as were one out of five sweet orange and their relatives. Every yuzu and its relatives, except hyuga-natsu, were self-compatible. Of the mandarin and its relatives, 14 out of 28 accessions were self-incompatible, whereas calamondin, a kumquat relative, and Hedzuka daidai of diverse origin were self-compatible. Thirty-one out of 65 accessions used in this study were self-incompatible. Of the self-incompatible accessions, clementine and ‘Ariake’, a hybrid of navel orange and clementine, were cross-incompatible. Thus, the incompatible genotypes of those two accessions were considered to be identical.
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Takeshi Kuniga, Ryoji Matsumoto2006 Volume 75 Issue 5 Pages 379-384
Published: 2006
Released on J-STAGE: September 25, 2006
JOURNAL FREE ACCESSGray mold (Botrytis cinerea Persoon) induced the accumulation of scoparone (6,7-dimethoxycoumarin) in the flavedo of fruit in all citrus species used in this study. The time-course of the accumulation of this compound was species dependent. In the fruit of ‘Kiyomi’ and Meiwa kumquat, scoparone accumulated gradually over several days after inoculation. No accumulation occurred in the non-inoculated citrus fruit. In several citrus species, including Tankan, ‘Seminole’, and ‘Ellendale’, Scoparone concentration increased up to 4 days after treatment. In ‘Murcott’, ‘Triumph’, and Yuzu, the maximum concentration was observed within 7 days of treatment. On the other hand, in ‘Imamura-unshu’, ‘Kawano Natsudaidai’, Ponkan, ‘Morita Navel’, Kinukawa, ‘Eureka’ lemon, kumquats, calamondin, and citrangequat, the increase in scoparone was much lower. These results suggest that scoparone is a phytoalexin induced by gray mold, accumulating in a broad range of citrus species.
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Kazuhiro Matsumoto, Jong-Pil Chun, Fumio Tamura, Yoko Kamamoto, Kenji ...2006 Volume 75 Issue 5 Pages 385-391
Published: 2006
Released on J-STAGE: September 25, 2006
JOURNAL FREE ACCESSSalt tolerance was tested in five Asian Pyrus rootstock species: Pyrus betulaefolia Bunge (strains C and N; P. betulaefolia C and P. betulaefolia N, respectively), P. calleryana Dcne. (strain No. 8; P. calleryana 8), P. pyrifolia Nakai, P. fauriei Schneid., and P. dimorphophylla Makino (strain No. 6; P. dimorphophylla 6). Four-month-old seedlings were subjected to each of 50 mM, 100 mM, 150 mM, and 200 mM NaCl solutions, and leaf injury, shoot growth, leaf water potential, and mineral uptake were evaluated. P. betulaefolia C showed the highest salt tolerance with no visible symptoms of injury even in the 200 mM NaCl treatment. P. betulaefolia N and P. dimorphophylla 6 also exhibited higher salt tolerance. In contrast, P. calleryana 8, P. fauriei, and P. pyrifolia exhibited lower salt tolerance with severe leaf injuries leading to defoliation and death. Leaf water potential decreased via NaCl treatment in all species and there was no difference among species. Sodium and Cl contents in the roots of all species increased within 2 weeks after NaCl treatment, although the differences among species and NaCl treatment was small. On the other hand, Na and Cl contents in leaves were different among species. The salt-sensitive species P. calleryana 8 and P. pyrifolia accumulated higher concentrations of Na and Cl in the leaves over 150 mM NaCl at 6 weeks after treatment compared to the salt tolerant species P. betulaefolia C. These results imply that P. betulaefolia C might have a key mechanism such as storage exclusion and/or transport-restriction between the shoot and root to depress the transport of Na and Cl to the upper plant parts, enabling a higher tolerance to NaCl.
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Takeshi Saito, Naoya Fukuda, Shigeo Nishimura2006 Volume 75 Issue 5 Pages 392-398
Published: 2006
Released on J-STAGE: September 25, 2006
JOURNAL FREE ACCESSTomato plants were grown using a nutrient film technique in a hydroponic system to evaluate the effects of starting time and duration of salinity treatment and the interaction between salinity and planting density on fruit yield and quality. The electrical conductivity (EC) of the nutrient solution was maintained until the anthesis of plants. Sodium chloride was added to the standard nutrient solution until EC 8.0 dS·m−1 and this level was maintained from the anthesis of the first flower truss until the fruit harvest (whole treatment); 8.0 dS·m−1 solution was applied from anthesis of the first truss until 20 days after anthesis (DAA) (early treatment) and from 20 DAA until the fruit harvest (late treatment). The average fruit weights in the whole, early, and late treatments were 46, 71, and 58% of the control weight, respectively. Fruit radius and cell size were also reduced under each salinity treatment; however, the estimated number of cells per fruit was not significantly affected by the salinity treatment. The levels of total soluble solids (Brix%) were 6.2 in the control and 9.9, 7.7, and 9.1 in the whole, early, and late treatments, respectively. Incidences of blossom-end rot were 0, 33, 25, and 16% in the control, whole, early, and late treatments, respectively. The influence of planting density (8.5–9.5 plants/m2) under saline conditions on fruit size and sugar content was not considerable unremarkable. The fruit yield at high planting density increased more than that at a low plating density under salinity treatment.
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Katsumi Shimomura, Keita Hirashima2006 Volume 75 Issue 5 Pages 399-402
Published: 2006
Released on J-STAGE: September 25, 2006
JOURNAL FREE ACCESSThe octoploid cultivated strawberry, Fragaria × ananassa Duch., is one of the most important commercial fruit species in Japan. Recently, cultivars developed in Japan are being used in other countries and the products are exported to Japan without the permission of breeders. Therefore, we need a way to protect breeders’ rights. So, we newly developed four simple sequence repeats (SSR) as markers to establish a more reliable method for the identification of strawberry cultivars (F. × ananassa). Especially, the frequency of two marker polymorphisms was high, and they facilitated the detection of 10 major Japanese commercial strawberry cultivars. The results indicated that the SSR markers were specific enough to identify octoploid strawberry cultivars for the protection of breeders’ rights.
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Kenji Ureshino, Yoshiko Tashiro, Yuka Takeda, Takeru Itabashi, Ikuo Mi ...2006 Volume 75 Issue 5 Pages 403-409
Published: 2006
Released on J-STAGE: September 25, 2006
JOURNAL FREE ACCESSFor the reduction of several undesirable traits, such as deciduousness and weak heat tolerance, of intersubgeneric hybrids between interspecific F1 hybrids of evergreen azaleas and a deciduous species (Rhododendron japonicum f. flavum), back cross with evergreen azaleas was conducted. Though pollen of the intersubgeneric hybrids was highly sterile, fertility was restored in a tetraploid plant (9027-5). Unilateral cross incompatibility was observed between the intersubgeneric tetraploid hybrid 9027-5 and evergreen azaleas, i.e., progenies obtained only in the cross with the tetraploid plant 9027-5 used as a pollen parent. Leaf color of most of the progenies was green, and hybridity was confirmed by isozyme analysis. PtDNA of the green progenies inherited from the seed parent (evergreen azaleas), and plastome-genome incompatibility between the plastid genome from evergreen azaleas and nuclear genome from R. japonicum f. flavum was not observed in the back cross.
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Mitsuru Taniwaki, Takanori Hanada, Naoki Sakurai2006 Volume 75 Issue 5 Pages 410-414
Published: 2006
Released on J-STAGE: September 25, 2006
JOURNAL FREE ACCESSA method for quantifying the texture of fresh commodities was developed. The texture data were obtained by acoustic measurements using a piezoelectric sensor and knife edge probe. The signal amplitude density was computed by summing up the amplitude of the texture signals and dividing by the data length. We designated this value as the texture index. An octave multi-filter was used to analyze the texture signals in the frequency domain between 0 Hz and 6400 Hz. Also, a technique of reducing periodical noise in the texture signals was developed. The noise data before the probe was inserted into a sample were subtracted from the raw data that consisted of both texture signals and noise. The methodology was applied to blanched bunching onion samples. Their signal amplitude densities showed the characteristics of blanched bunching onion texture. Also, analyzing the texture signals in the lowest frequency band (0–50 Hz) revealed the leaf sheath structure of the blanched bunching onion tissue.
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Shinichiro Kuroki, Minami Tohro, Naoki Sakurai2006 Volume 75 Issue 5 Pages 415-420
Published: 2006
Released on J-STAGE: September 25, 2006
JOURNAL FREE ACCESSA portable device for measuring an elasticity index in the field was newly developed. The portable device produces accurate and reproducible measurements of the elasticity index of melon fruit. Using this device, changes in the elasticity index during cultivation were investigated. The elasticity index essentially decreased in the early development of the fruit, but showed a fluctuating level in the late stage of development. Each elasticity index of the fruit at different flowering dates, cultivars, and locations in the greenhouse was monitored. It was also shown that the change in the elasticity index within a day was not due to variation in ambient temperature.
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ORIGINAL ARTICLE (JAPANESE)
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Yuka Nakano, Shin-ichi Watanabe, Hiroki Kawashima, Masuyuki Takaichi2006 Volume 75 Issue 5 Pages 421-429
Published: 2006
Released on J-STAGE: September 25, 2006
JOURNAL FREE ACCESSDaily nutrient additions reduced nutrient supply and concentration in the hydroponic solution without affecting fruit yield and quality of tomato ‘Renaissance’, grown during the winter of 2003–2004 and the summer of 2004. The results were compared to those obtained by the conventional EC-based plots. In the daily nutrient addition plot, all nutrients were supplied according to water uptake by tomato plants under three different application rates (Low, Medium, and High nutrient solution). The nutrient levels in the Medium treatment were reduced, except for sulfur, to 53–66% with respect to the EC-based treatment in the winter experiment and 73–77% in the summer experiment. Nitrogen and phosphorus concentration in the Low and Medium nutrient solution did not exceed 10 mg·L−1 and 3 mg·L−1, respectively, except for 30 days after the transplanting. The total amount of macro nutrient absorbed and dry weight accumulated by leaves increased with increasing nutrient supply. The yields from the Medium and High treatments were equal to the EC-based treatment. Daily nutrient addition increased soluble solids content and ascorbic acid, but it did not influence titratable acidity in fruits. It was estimated that the addition of 50 mg N·plant−1·day−1 is adequate to maintain normal growth by tomato plants, provided the water uptake was kept at 0.5 L·plant−1·day−1. N could be increased to 130 mg·plant−1·day−1 with an increase in water uptake. Thus, this system of nutrient additions that can be easily regulated could increase productivity of tomato fruits by preventing excess vegetative growth, and simultaneously reduce the environmental impact of wastewater.
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