Japanese Apricot Laboratory

Minabe, Japan

Japanese Apricot Laboratory

Minabe, Japan
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Tsuchida Y.,Japanese Apricot laboratory | Yakushiji H.,Japan National Agriculture and Food Research Organization
Horticulture Journal | Year: 2017

With the continuing trend of global warming, the adverse impact of high temperature and the inevitably accompanying drought stress on the growth of Japanese apricot trees (Prunus mume Siebold et Zucc.) are of concern. Therefore, the effects of these factors on photosynthesis and carbohydrate translocation were analyzed. An investigation was conducted at average daytime temperatures of 24°C, 30°C, and 34°C under both irrigated and drought conditions. The 34°C temperature was higher than the open air temperature by 5°C. Stable isotope13C was administered to trees to determine carbohydrate positioning. Under the drought stress condition, the photosynthetic rate declined accompanied by temperature elevation, and at the highest temperature of 34°C,13C concentrations in the twigs and roots were lower than those in the irrigated trees at 24°C. Two-way analysis of variance revealed a trend of13C translocation to the young organs above ground, and old organs, while roots were affected by water status, temperature, and their combination, respectively. In the irrigated trees, the photosynthetic rate reduction was not detected, even at higher temperatures. However, translocation incompetence reflecting a decline in13C concentration in the roots was observed at 34°C. These results indicate that the permissible diurnal average temperature during summer for the growth of Japanese apricot trees is approximately up to 30°C, and in the temperature range around this irrigation is helpful to facilitate regular functioning of carbohydrate translocation under drought stress conditions. © 2017 The Japanese Society for Horticultural Science (JSHS), All rights reserved.

Kitamura Y.,Japanese Apricot Laboratory | Kitamura Y.,Kyoto University | Yamane H.,Kyoto University | Yukimori A.,Japanese Apricot Laboratory | And 4 more authors.
HortScience | Year: 2017

Flower bud development and the timing of blooming are mainly affected by genotype-dependent chilling requirements (CRs) during endodormancy and subsequent heat requirements (HRs) during ecodormancy. However, little information is available regarding the responses of flower buds to temperatures during endodormancy and ecodormancy in japanese apricot. We exposed japanese apricot ‘Nanko’ trees to various temperatures to estimate the CRs and HRs using development index (DVI) models specific for the endodormant (DVIendo) and ecodormant (DVIeco) stages. These models were based on the experimentally determined development rate (DVR). The DVRendo value was calculated as the reciprocal of the chilling time required to break endodormancy. The relationship between the DVRendo value and temperature was estimated using a three-dimensional curve. Our results indicated that 5–6 °C was the most effective temperature for breaking endodormancy in ‘Nanko’ flower buds. Additionally, exposure to L3 °C negatively affected endodormancy release, whereas 15 °C had no effect. We also determined that the DVReco values for temperatures between 5 and 20 °C were the reciprocal values of the time required for blooming after endodormancy release. The values outside this range were estimated using linear functions. The DVI was defined as the sum of the DVR values ranging from 0 to 1. Models for predicting the blooming date were constructed using the functions of sequentially combined DVIendo and DVIeco models. The accuracy of each model was assessed by comparing the predicted and actual blooming dates. The prediction of the model in which DVIeco = 1 corresponded to a 40%blooming level and DVIeco =0 was set to DVIendo = 0.5 had the lowest root mean square error (RMSE) value (i.e., 3.11) for trees in commercial orchards exposed to different climates. Our results suggest that the developed model may have practical applications. © 2017, American Society for Horticultural Science. All rights reserved.

Tsuchida Y.,Japanese Apricot Laboratory | Yakushiji H.,Japan National Agriculture and Food Research Organization | Oe T.,Japanese Apricot Laboratory | Negoro K.,Japanese Apricot Laboratory | And 6 more authors.
Journal of the Japanese Society for Horticultural Science | Year: 2014

Japanese apricot (Prunus mume Siebold & zucc.) fruits of 'Nanko' have softer flesh than those of 'Gojiro'. Therefore, there are differences in the processability of these cultivars. We investigated the characteristics of cell-wall polysaccharide degradation that significantly affects fruit firmness in these 2 cultivars at unripe, ripe, and drop stages. Fruit firmness of 'Gojiro' was maintained during unripe and ripe stages and decreased after the ripe stage, while that of 'Nanko' decreased constantly and was lower than that of 'Gojiro' at ripe and drop stages. Amount of the pectin and the hemicellulose substances decreased commonly in 'Gojiro' and 'Nanko' in the process of fruit softening, in addition, decrease in mol wt of these polysaccharides significantly synchronized with decrease in fruit firmness, suggesting that degradation of the pectin and the hemicellulose cause the softening of Japanese apricot fruits. The amount of neutral sugar (NS) and uronic acid (UA) in the pectin fraction and NS in the hemicellulose fraction in 'Nanko' decreased more than in 'Gojiro'. Moreover, the cellulose content of 'Nanko' decreased during the fruit-softening process. These results suggest that higher degradation of pectin, hemicellulose, and cellulose in 'Nanko' fruits would result in softer fruits than 'Gojiro'. © 2014 The Japanese Society for Horticultural Science (JSHS), All right reserved.

Tsuchida Y.,Japanese Apricot laboratory | Yakushiji H.,Japan National Agriculture and Food Research Organization | Jomura N.,Japanese Apricot laboratory | Okamuro M.,Japanese Apricot laboratory | And 3 more authors.
Scientia Horticulturae | Year: 2015

Changes in concentration of carbohydrates in three forms-soluble sugars, starch, and cell-wall material (CWM) assimilated each month from summer (August; 2 months after harvest) to late fall (November; just before defoliation)-in organs of Japanese apricot (Prunus mume Siebold et Zucc.) Nanko" were determined until May of the following season by providing 13CO2. 13C concentrations in the nonstructural carbohydrates (soluble sugar and starch) in the foliar and flower buds were higher than those in the current twigs and fine roots, suggesting that these organs are large sinks of reserve carbohydrates. However, they decreased sharply along with growth and were low in all the organs at the beginning of May. In contrast, a large amount of 13C was fixed in the CWM of older twigs. These results indicate that reserve carbohydrates contribute to the growth of young shoots and fruits until the beginning of May, after which their growth depends on current assimilates. Carbohydrates assimilated in August-November were mainly transported to twigs, roots, trunk, and flowers, respectively. These findings show that carbohydrates assimilated in each month contribute to different organs. Thus, leaves should be maintained healthy until defoliation to produce substantial amounts of carbohydrate reserves for stable fruit production from Japanese apricot tree. © 2015 Elsevier B.V.

Tsuchida Y.,Japanese Apricot laboratory | Yoshihara T.,Japan Central Research Institute of Electric Power Industry | Yakushiji H.,Japan National Agriculture and Food Research Organization | Jomura N.,Japanese Apricot laboratory | And 3 more authors.
Journal of the Japanese Society for Horticultural Science | Year: 2012

The changes in the volume of carbohydrates assimilated each month from summer (Aug.; 2 months after harvest) to late fall (Nov.; just before defoliation) in each organ of the Japanese apricot (Prunus mume Siebold & Zucc.) 'Nanko' tree were determined until May the following season. The 13C concentrations in the young fruits and new leaves were significantly low at the beginning of May. This phenomenon indicates that their growth depends on current instead of reserve carbohydrates. In May, carbohydrates assimilated in Aug., Sep., and Oct. were mainly transported to 2-year-old twigs (current twigs at 13C feeding time), roots, and trunk, respectively. Carbohydrates assimilated in Nov. were mainly transported to the flower buds with subsequent flowering at a significantly greater level, and barely transported to the perennial organs. These findings show that carbohydrates that are assimilated each month contribute to different organs and, particularly, that those assimilated in Nov. are important for the growth of flower buds and subsequent flowers; therefore, healthy leaves should be maintained until defoliation for stable production of the fruit of the Japanese apricot tree. © 2012.

Kitamura Y.,Kyoto University | Kitamura Y.,Japanese Apricot Laboratory | Takeuchi T.,Kyoto University | Yamane H.,Kyoto University | Tao R.,Kyoto University
Journal of Horticultural Science and Biotechnology | Year: 2016

In temperate deciduous fruit crops such as Prunus spp., bud endodormancy is an important physiological phase affecting the timing of blooming and subsequent fruit development. Japanese apricot (Prunus mume) bears unmixed flower buds, separate from vegetative buds, that bloom slightly more than a month before vegetative bud burst. Seasonal expression of Prunus mume DORMANCY ASSOCIATED MADS-box genes (PmDAMs) has previously been analyzed only in vegetative buds, with an association between these genes and flower bud endodormancy release not yet confirmed. In this study, we performed a seasonal expression analysis of PmDAM1-6 genes in flower buds of two Japanese apricot genotypes - namely, high-chill and low-chill cultivars. The analysis revealed that PmDAM3, PmDAM5, and PmDAM6 expressions are closely associated with dormancy release in both flower and vegetative buds. In addition, a yeast two-hybrid screening demonstrated that PmDAM6 can interact in yeast with the homolog of Arabidopsis SOC1 (PmSOC1). Synchronized expression patterns were detected in PmDAM6 and PmSOC1 during dormancy release in flower buds of the two genotypes. Taken together, these results suggest that the dimer of PmDAM6 and PmSOC1 may play a role in the regulation of dormancy transition and blooming time in Japanese apricot flower buds. © 2016 The Journal of Horticultural Science & Biotechnology Trust.

Kishi M.,Japanese Apricot Laboratory | Matsuno S.,Wakayama Prefectural Museum of Natural History
Japanese Journal of Applied Entomology and Zoology | Year: 2015

The sex of adults of Phenolia (Lasiodites) picta (MacLeay) is distinguished by the morphology of the pygidium and the presence of a well sclerotized tergite VIII in males. These differences are visible under a binocular microscope at a low magnification (15×). As the difference between the sexes can be distinguished without killing specimens, it can be used to observe the specific behaviors of females and males and in ecological research.

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