Kaki Thunb Research Articles

Pharmacological Activity of Compounds Extracted from Persimmon Peel (Diospyros kaki THUNB.)

Persimmon peels (Diospyros kaki THUNB.) are discarded during the production of dried fruit. The 2-methoxy-4-vinylphenol (8) which is component of persimmon peel had high antioxidant activity on the DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging assay and SOD (superoxide dismutase) assay. And (8) had higher tyrosinase inhibiting activity than that of arbutin using both L-tyrosine and L-DOPA as substrates. In addition, tyrosinase inhibiting activity of synthesized 2-methoxy-4-vinylphenol glycoside (8a) was studied. (8a) had tyrosinase inhibiting activity, suggesting that (8a) has possibilities for ingredient of cosmetics that are possessed of whitening effect.

Conversion of RFLP Markers for the Selection of Pollination-Constant and Non-Astringent Type Persimmons (Diospyros kaki Thunb.) into PCR-Based Markers

Persimmon (Diospyros kaki Thunb.) cultivars are classified into 4 types depending on the relationship between astringency of the mature fruit and the effect of seeds on the loss of astringency, and only pollination-constant and non-astringent (PCNA)-type persimmons stably lose fruit astringency as a part of fruit development. This is a recessive trait, regarded to be controlled by a single locus, namely, the AST locus, which has a polysomic nature. Thus far, we have identified 2 restriction fragment length polymorphism (RFLP) markers, namely, A1 and A2, each of which is separately linked to a different AST allele, and proved that the RFLP markers were useful for selecting PCNA-type persimmons. This study was conducted to convert the RFLP markers into polymerase chain reaction (PCR)-based markers. We isolated and characterized genomic regions corresponding to each RFLP marker by inverse PCR. Two primer pairs, E4/E9r and E4/A2r, were designed to generate 2 sequence characterized amplified region (SCAR) markers, i.e., PCR-A1 and PCR-A2, respectively. The PCR-A1 and PCR-A2 markers cosegregated with the A1 and A2 markers, respectively, in ‘Nishimura-wase’-derived progenies. Although the primer pair E4/A2r did not produce the PCR-A2 marker in the FU-275, which is a progeny derived from ‘Aizumishirazu’, all non-PCNA-type offspring but no PCNA-type offspring showed the PCR-A1 marker using the primer pair E4/E9r. Thus, it was revealed that the SCAR markers were useful for selecting PCNA-type offspring in these progenies. On the other hand, disruption of the relationship between the markers and the AST locus was observed in the KU-325, derived from ‘Kurokuma’, indicating that the selection of PCNA-type offspring using PCR-based markers is not effective for progeny derived from ‘Kurokuma’. Herein, we discuss the possibility of applying PCR-based markers to genetic studies.

Mechanism of Browning Occurring during the Processing of Semi-dried Persimmons

To investigate the mechanism of browning occurring during the processing of semi-dried ‘Atago’ persimmon (Diospyros kaki Thunb.) fruit, the changes in several components related to enzymatic and non-enzymatic browning were determined. The browning of semi-dried persimmons developed when the water content of fruit decreased to about 50% or less, and hand massage (HM) treatment promoted both the drying process and development of browning. The polyphenol content as a substrate of polyphenol oxidase (PPO) markedly decreased during the first 7 days of drying before the occurrence of browning. PPO activity gradually decreased and was lower in dry + HM than dry treatment alone during drying. The ascorbic acid (AsA) content decreased and HM accelerated the reduction by 7 days of drying. Dehydroascorbic acid (DHA) also decreased with stagnation in the mid-stage during 14 days of drying and was lower in dry + HM than dry treatment alone during the latter period of drying. Furfural, a non-oxidative degradation product of AsA, started to increase from 4 or 10 days of drying in dry + HM or dry treatment, respectively. Reducing sugars, fructose and glucose, markedly increased for the first 4 days with a concomitant decrease in the sucrose content, and were higher in dry + HM than dry treatment. The content of amino acids gradually decreased, and no difference was observed between treatments. Hydroxymethylfurfural (HMF), as an intermediate product from fructose to brown pigments, decreased during drying and was lower in dry + HM than dry treatment alone. These results suggest that the oxidative and non-oxidative degradation of AsA would contribute markedly to the browning of semi-dried persimmon fruit, and enzymatic browning by PPO and the Maillard reaction between amino acids and reducing sugars might not play an important role.

Development of Japanese Persimmon Core Collection by Genetic Distance Sampling Based on SSR Markers

ABSTRACTCore collections have been developed in many seed crops, but the corresponding examples in clonal crops were very few. In China there were plenty of Japanese persimmon (Diospyros kaki Thunb.) germplasms. Using 117 Japanese persimmon accessions from a primary core collection, alternative Nei & Li genetic distance sampling methods based on 11 SSR primer pairs have been compared for developing a core collection. The relative success of the different methods was assessed by counting number of alleles, percentage of polymorphic loci, Shannon diversity index and Nei 's gene diversity index. The results showed that 24 candidate core collections were obtained according to 24 different Nei & Li genetic distances. Among 24 core collections, a core collection, containing 15 accessions, proved to be the best one when the value of genetic distance was 0.17. The number of alleles and percentage ofpolymorphic loci of this best core collection were the same as that of primary core collection, and both Shannon diversity index and Nei's gene diversity index were the highest among the 24 core collections.

The growth of tannin cells from before flowering to fruit maturity and astringency in Japanese persimmons

SummaryChanges in the growth of tannin cells were investigated in Japanese persimmon (Diospyros kaki Thunb.) to determine the relationship between astringency and fruit anatomy. In the first Experiment, samples of ovaries and fruit were collected from astringent ‘Hiratanenashi’ and non-astringent ‘Matsumotowase-Fuyu’ persimmons, from flowering to fruit harvest. In the second experiment, samples were collected from ‘Fuyu’, ‘Zenjimaru’, ‘Nishimurawase’, ‘Saijo’, ‘Yokono’, and ‘Tonewase’, from fruit set to harvest. Tannin cells appeared approx. 20 d before anthesis in ‘Hiratanenashi’ and ‘Matsumotowase-Fuyu’, with a period of rapid cell division rather than enlargement, which stopped 70 d after anthesis (DAA) in ‘Hiratanenashi’ and 28 DAA in ‘Matsumotowase-Fuyu’. Tannin cells were larger in the astringent cultivars than in the non-astringent cultivars, whereas the numbers of tannin cells and the sizes of the parenchyma cells in the fruit mesocarp were similar. Tannin cells appeared to be differentiated in the mature ovary, and possibly protect the young fruit from pathogens and pests.

フジコナカイガラムシの土着天敵Ｄｉａｄｉｐｌｏｓｉｓ ｈｉｒｔｉｃｏｒｎｉｓ（ハエ目：タマバエ科）の発育ゼロ点と有効積算温度，羽化時刻

In southwestern Japan, the Japanese mealybug Planococcus kraunhiae (Kuwana) (Hemiptera: Pseudococcidae) is one of the most serious pests that attack the Japanese persimmon Diospyros kaki Thunb. (Ebenaceae). Diadiplosis hirticornis (Felt) (Diptera: Cecidomiidae) is thought to be an important natural enemy of P. kraunhiae. In order to establish control measures that use D. hirticornis to control the population of the mealybug, we need fundamental information on the ecological and behavioral characteristics of D. hirticornis. As the first step, we investigated its developmental velocity at 17.5, 20, 22.5, 25, 27.5, 30, and 32.5°C and its hourly adult emergence pattern. The lower developmental threshold was found to be 11.1°C for both male and female individuals. For the whole stages from egg to adult, the day-degrees above the developmental threshold was 232.6 for male and 238.1 for female individuals. D. hirticornis was confirmed to be diurnal. A majority of the males emerged between 6 : 00 and 12 : 00, while most females emerged between 8 : 00 and 18 : 00.

Scoring and Girdling, but not GA3, Increase Yield without Decreasing Return Bloom in ‘Triumph’ Persimmon

The persimmon (Diospyros kaki Thunb.) cultivar Triumph is prone to poor fruit set, particularly in young orchards, in both Israel and South Africa where it is mostly grown. Two applications of 20 mg·L−1 gibberellic acid (GA3) at 30% and 70% full bloom (FB) are recommended as the industry norm to increase fruit set, but results obtained are often unsatisfactory. We conducted experiments during the 2005–06 and 2006–07 seasons in a young orchard (less than 5 years old) and a full-bearing orchard to determine the efficacy of GA3 application and scoring or girdling during FB to increase fruit set and yield in ‘Triumph’ persimmon. We also established the effect of 2005–06 treatments on return bloom in 2006–07. Although GA3 treatments were ineffective in increasing fruit set and reduced cumulative yield over the two seasons as a result of a reduction in return bloom, scoring increased the cumulative yield by 50% compared with the untreated control and by 92% compared with GA3 application in the young orchard. In the full-bearing orchard, scoring or girdling increased the cumulative yield over the 2005–06 and 2006–07 seasons by 52% compared with the industry standard GA3 application and by 22% compared with trees that received scoring/girdling in addition to GA3. Hence, scoring or girdling did not entirely offset the negative effect of GA3 application on return bloom. The increase in fruit numbers in response to fruit set treatment brought about a reduction in fruit mass. In conclusion, the ineffectiveness of GA3 in increasing fruit set and its negative effect on return bloom do not justify its further use to improve fruit set in young or full-bearing ‘Triumph’ orchards in South Africa. Either scoring or girdling can be used to increase yield but will need to be accompanied by pruning and thinning strategies to achieve adequate fruit size and to prevent the onset of alternate bearing resulting from overcropping.

Development of retrotransposon primers and their utilization for germplasm identification in Diospyros spp. (Ebenaceae)

Retrotransposons play an important role in plant genetic instability and genome evolution. Retrotransposon-based molecular markers are valuable tools to reveal the behavior of retrotransposons in their host genome. In this study, suppression polymerase chain reaction was used, for the first time, to develop retrotransposon long terminal repeat (LTR) and polypurine tract (PPT) primers in Japanese persimmon (Diospyros kaki Thunb.), which were then employed for germplasm identification by means of interretrotransposon-amplified polymorphism (IRAP), sequence-specific amplified polymorphism (SSAP) and retrotransposon-microsatellite-amplified polymorphism (REMAP) molecular markers. The results showed that 16 out of 26 primers produced expected amplifications and abundant polymorphisms by IRAP in 28 genotypes of Diospyros. Moreover, some of these primers were further successfully used in REMAP and SSAP analysis. Each type of molecular markers produced unique fingerprint in 28 genotypes analyzed. Among the primers/primer combinations, two IRAP primers and four SSAP primer combinations could discriminate all of the germplasm solely. Further comparative analysis indicated that IRAP was the most sensitive marker system for detecting variability. High level of retrotransposon insertion polymorphisms between bud sports were detected by IRAP and SSAP, and the primers/primer combinations with powerful discrimination capacity for two pairs of bud sports lines were further obtained. Additionally, possible genetic relationships between several Japanese persimmon were discussed. To our knowledge, this is the first report on the development of retrotransposon LTR and PPT primers in Diospyros, and the retrotransposon primers developed herein might open new avenue for research in the future.

Growth Characteristics of a Small-fruit Dwarf Mutant Arising from Bud Sport Mutation in Japanese Persimmon (Diospyros kaki Thunb.)

Fruit size is one of the most important traits that affect the economic value of fruit. In persimmon (Diospyros kaki Thunb.), somatic and bud-sport mutations that affect the fruit traits are frequently observed. Recently, a small-fruit mutant, ‘Totsutanenashi’ (TTN), was discovered in Japan as a bud-sport mutant of the leading cultivar Hiratanenashi (HTN). In this study, we investigated the morphological and physiological characteristics of TTN and HTN focusing on the tree architecture, fruit size, and the fruit flesh chemical composition. The objectives of the study were to evaluate the potential horticultural use of TTN and to characterize the differences between HTN and TTN. Both TTN and HTN are nonaploid plants, indicating that a difference in ploidy is not the cause of the small-fruit mutation. The vegetative growth of trees and tissue-cultured shoots of TTN was more compact than that of HTN. The floral organs of TTN appeared similar to those of HTN before flowering, but the TTN flowers opened earlier, resulting in smaller ovaries than in HTN flowers. The fruit size of TTN was consistently lower than that of HTN at all fruit developmental stages. TTN fruit had a higher sugar content and a higher proportion of sucrose to total sugars than HTN fruit. TTN fruits contained lower levels of secondary metabolites such as soluble tannins and ascorbate than HTN fruits. These results suggest that the fruit size mutation also affects the fruit biochemistry, leading to alterations in the fruit flesh composition. TTN may be a valuable genetic resource because compact trees require less labor and maintenance, and small, sweeter fruits may meet the various needs of consumers. The use of TTN in studies of the genetic control of fruit size is also discussed.

Postharvest quality evaluation of “Fuyu” and “Taishuu” persimmons using a nondestructive vibrational method and an acoustic vibration technique

We investigated time-course changes in the elasticity index (EI) and texture index (TI) of two persimmon ( Diospyros kaki Thunb.) cultivars (“Fuyu” and “Taishuu”) during the postharvest period. EI was determined using the formula EI = f 2 2 m 2 / 3 , where f 2 is the second resonance frequency of a sample, and m is the mass of the sample. A nondestructive vibrational method employing a laser Doppler vibrometer (LDV) was used for measuring the second resonance frequency ( f 2 ) of the persimmon samples. The changes in the EI of both cultivars showed quasi-exponential decays. An improved texture measurement device was used for measuring the TI of the cultivars. The TI was defined by ( 1 / T ) ∑ | V i | , where T (s) is the sampling period and V i (V), the amplitude of each data point. The pattern of time-course changes in TI differed between “Taishuu” and “Fuyu” persimmons; a sharp decline was observed in the TI of “Fuyu.” Along with the sensory test, we determined the optimum eating ripeness of persimmons in terms of their EI to be 2.9–6.0 × 10 4 kg 2/3 Hz 2 (“Taishuu”) and 4.8–6.4 × 10 4 kg 2/3 Hz 2 (“Fuyu”).

Expressed sequence tags from persimmon at different developmental stages

Persimmon (Diospyros kaki Thunb.) is an important fruit in Asian countries, where it is eaten as a fresh fruit and is also used for many other purposes. To understand the molecular mechanism of fruit development and ripening in persimmon, we generated a total of 9,952 expressed sequence tags (ESTs) from randomly selected clones of two different cDNA libraries. One cDNA library was derived from fruit of "Saijo" persimmon at an early stage of development, and the other from ripening fruit. These ESTs were clustered into 6,700 non-redundant sequences. Of the 6,700 non-redundant sequences evaluated, the deduced amino acid sequences of 4,356 (65%) showed significant homology to known proteins, and 2,344 (35%) showed no significant similarity to any known proteins in Arabidopsis databases. We report comparison of genes identified in the two cDNA libraries and describe some putative genes involved in proanthocyanidin and carotenoid synthesis. This study provides the first global overview of a set of genes that are expressed during fruit development and ripening in persimmon.

Fruit Cracking in 'Saijo' Japanese Persimmons (Diospyros kaki Thunb.) during Soft Ripening

After storage for several weeks at 0°C, 'Saijo' persimmons (Diospyros kaki Thunb.) were treated with ethylene to obtain soft-ripened fruit. Fruit cracking occurred during soft ripening. There was a significant positive correlation (r=0.707*) between cold storage period and the ratio of the number of cracked persimmons to the total number of treated persimmons. Shallow cracks seemed to occur in linear groups on the cuticular layer but did not reach the pericarp. Most of them were seen along the ventral suture near the fruit apex. Ruptures occurred mostly on the lateral side of the fruit. The location of shallow cracks and ruptures on the fruit were considerably close, suggesting that the ruptures developed from the shallow cracks. The occurrence of ruptures was observed 2.0 to 4.5 days after the beginning of ethylene treatment. Ruptures elongated afterward and finally became 100-140mm long. Artificial deep injuries in the fruit significantly induced fruit cracking more effectively on the skin near the fruit apex than on the equatorial zone of the fruit. It was suggested that the development of shallow cracks during cold storage prior to ethylene treatment causes cracking.

The relationship between fruit size and cell division and enlargement in cultivated and wild persimmons

SummaryTo determine the anatomical basis for differences in fruit size in Japanese persimmon (Diospyros kaki Thunb.), the number and sizes of parenchymal cells were measured in four astringent cultivars and in wild D. lotus over a single season in Japan. Fruit weight at harvest correlated with the final number of parenchymal cells (r = 0.95*) and their size (r = 0.92*). There was also a correlation between fruit diameter and the number of cell layers at full bloom (r = 0.93*), which increased 1.7 – 1.9-fold during fruit development.The duration of cell division and the sizes of the cells at full bloom were similar among the cultivars, whereas mean parenchymal cell lengths increased by 7.7-, 6.7-, 5.4-, 5.0- and 3.8-fold from full bloom to harvest in ‘Otanenashi’ (average fruit diameter = 96 mm), ‘Hiratanenashi’ (77 mm), ‘Saijo’ (54 mm), ‘Tsurunoko’ (44 mm), and D. lotus (20 mm), respectively. The final size of tannin cells was larger in ‘Otanenashi’ and ‘Hiratanenashi’ than in the other cultivars, including the wild species.These results indicate that the size of fruit at harvest was determined by the number of cells at full bloom, and their expansion during fruit development.

RFLP Markers for the Selection of Pollination-constant and Non-astringent (PCNA)-Type Persimmon and Examination of the Inheritance Mode of the Markers

We investigated marker-assisted selection of the pollination constant and non-astringent (PCNA) trait and inheritance modes of the marker locus in persimmon (Diospyros kaki Thunb.) using restriction fragment length polymorphism (RFLP) analysis. In two backcross progenies, FU-170 and FU-275, 5 of 71 and 23 of 101 offspring, respectively, were judged as PCNA genotype by the marker phenotype. The astringency type of individual offspring was determined by measuring the size of tannin cells and soluble tannin content in mature fruit, thus confirming complete co-segregation of RFLP markers and the non-PCNA phenotype in 32 and 68 fruit-obtainable offspring from FU-170 and FU-275, respectively; therefore, RFLP markers can be used for PCNA genotype detection. Their segregation ratio deviated significantly from that of disomic inheritance. We also discuss the possibility of polysomic inheritance of RFLP markers.

Functional Component Contents in Mature Leaves, Young Shoots, and Adventitious Shoots of Japanese Persimmon 'Saijo'

The mature leaves of Japanese ‘Saijo’ persimmon (Diospyros kaki Thunb.) are consumed as ingredients in health foods and teas. Levels of ascorbic acid and polyphenols were compared between the mature leaf (M-leaf), young shoot (T-shoot; cultured by water-soaking twigs grown the previous year) and adventitious shoot (A-shoot; obtained from orchard trees). The level of total ascorbic acid (T-AsA) was highest in M-leaves, and though the levels of polyphenols were high in M-leaf and A-shoot, they were remarkably low in T-shoot. Isoquercitrin and astragalin levels were highest in A-shoot, followed by M-leaf, and then T-shoot.

Generation of Nonaploid Persimmons (Diospyros kaki Thunb.) by Embryo Culture of Imperfect Seeds Derived from a Cross between ‘Fuyu’ and ‘Taishuu’

We obtained nonaploid plants by embryo culture of imperfect seeds derived from a cross between ‘Fuyu’ and ‘Taishuu’, both of which are commercially important persimmon cultivars. Furthermore, we aimed to clarify the origin of nonaploid plants derived from imperfect seeds. Of 1078 seeds, 68 were imperfect; this accounted for 6.3% of the total number. Ten of the 68 seeds germinated into seedlings, and two produced abnormal plantlets without meristems at both the shoot apex and root tip. The remaining eight produced normal-appearing plantlets with normal growth. Two seedlings were recovered from the abnormal plantlets via callus, and grew vigorously in the greenhouse. Cytogenetic analysis confirmed that these two seedlings were nonaploids. Parental analysis using four simple sequence repeats (SSR) markers, D.CT-13, 24, 61 and 179, showed that each nonaploid seedling had alleles originating from the parents, indicating that they were generated by syngamy. The two nonaploid seedlings had alleles of 222 bp at D.CT-61, which is peculiar to the pollen parent, ‘Taishuu’, whereas they did not have an allele of 136 or 140 bp at D.CT-179, which is peculiar to the seed parent, ‘Fuyu’. These results suggest that they might be derived from fertilization of a reduced female gamete with an unreduced male gamete.

Antibacterial Effects of Diospyros Kaki Thunb. Extract against Cariogenic Bacteria

Antibacterial Effects of Diospyros Kaki Thunb. Extract against Cariogenic Bacteria

Artificial Ripening of ‘Shiraz’ Persimmon (Diospyros kaki Thunb. cv. ‘Shiraz’) Prior to Marketing

Although it is one of the traditional fruits, persimmon production in Iran is only about 7,320 tons annually and there has been a decrease in cultivated acreage. The decrease in persimmon consumption can be attributed to the unpleasant astringency of the local Iranian cultivars. The producers' and handlers' lack of knowledge of techniques for removing astringency before sending the fruit to market has greatly influenced this issue. This study was conducted in order to develop recommendations for a simple and economical method for removing the fruit astringency of local cultivars. Fruits of a commercial cultivar (cv. ‘Shiraz’) in Fars province, Iran were harvested at the local commercial maturity stage (breaker stage). The fruits were dipped in ethanol (20, 35 and 50%), acetic acid (3, 6 and 10%), commercial vinegar, hot water (60°C) and tap water as control for 30 min. Some qualitative characteristics such as total soluble solids (TSS), vitamin C, total acids, pH and tannic acid of the treated fruits besides fresh weight changes were measured at 4-day intervals after storage at room temperature. Results indicate that vitamin C and TSS were highest in the 20% ethanol, hot water and 35% ethanol treatments. Total acid was highest in 10 and 6% acetic acid treatments. Tannins were highest in the control treatment and lowest in the 20% ethanol, hot water followed by 35% ethanol. Fruit juice pH was also highest in the 20 and 35% ethanol and hot water. Although tannic acid and total acid declined after treatment, fruit juice pH and TSS increased. Weight loss was lowest in the ethanol 20, 35 and 50%, and hot water treatments, respectively. Results suggest the use of 20% ethanol treatment with ‘Shiraz’ persimmon before short storage and supply to markets would be beneficial in improving consumer acceptance besides being commercially economical and practical.

日照時間が促成栽培のカキ'刀根早生'の花芽分化に及ぼす影響

日照時間が促成栽培のカキ'刀根早生'の花芽分化に及ぼす影響

Relationship of European persimmon (Diospyros kaki Thunb.) cultivars to Asian cultivars, characterized using AFLPs

Sixty one persimmon (Diospyros kaki Thunb.) selections, including 17 Italian, 11 Spanish, 13 Japanese, six Korean, five Chinese, one Israeli, and eight of unknown origin, were evaluated for genetic differences by AFLP analysis. Relationships among cultivars were evaluated by UPGMA clustering, Neighbor Joining, and MultiDimensional Scaling. While similarities among groups were generally less than 0.60, both UPGMA and Neighbor Joining separated European and Asian cultivars. Spanish and Italian cultivars were not separated by any of the analyses, suggesting that they share a common gene pool, while Japanese, Chinese and Korean cultivars formed distinct clusters. Diversity within groups was greater than diversity between groups. Most cultivars were quite polymorphic (only 0.60–0.80 similarity between cultivars). In addition, the presence of several Japanese cultivars in the European group and a group of European cultivars nested between Chinese and Korean groups suggest that similar, but different progenitors were used in the development of the present European cultivars. ‘Kaki Tipo’ selections from different sources were clearly different by AFLP analysis, indicating that they are separate cultivars.