Vibrio parahaemolyticus is known to exist in a viable but nonculturable state when incubated at low temperature under starvation. It has long been debated whether the culturable cells which appear after temperature upshift are the result of true resuscitation or regrowth of a few residual culturable cells. Starved V. parahaemolyticus cells at 4°C reached the nonculturable stage in about 12 days. The true resuscitation of nonculturable cells of V. parahaemolyticus occurred after spreading them onto an agar medium supplemented with H2O2‐degrading compounds such as catalase or sodium pyruvate. The proposed method may be applicable to detecting the enteropathogen from environmental samples.

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Pointed gourd (Trichosanthes dioica Roxb.) (2n = 2x = 22) is a dioecious cucurbit vegetable and green fruit that is edible after cooking. Consumers prefer to consume seedless or less-seeded fruit because seeds are unpalatable due to their hard coats. Therefore, the cross compatibility between the diploid and induced tetraploid will be helpful for seedless or less-seeded fruit production. Thus, the present study was conducted using mature seeds that were immersed in 0.05%, 0.1%, and 0.5% colchicine for 24, 48, and 72 h to induce tetraploids. These tetraploids were used as parents (male or female) in the inter-ploidy and intra-ploidy crosses. A flow cytometric analysis confirmed the induction of three tetraploids at 0.5% colchicine for 48 and 72 h soaking periods. Among these, two (2) females and one (1) male were differentiated after flower initiation. Crossing between the tetraploid's maternal and diploid paternal parent (4x × 2x), which were revealed to be compatible, resulted in a similar fruit set rate and shape as those of the diploid. In addition, a seed number of 4x × 2x produced fruits that were drastically reduced to 1.8 seeds per fruit, whereas the natural diploid fruits had 26.4 seeds per fruit. These findings suggest that colchicine-induced tetraploid females are important genetic resources for less-seeded fruit production. The genetic stability of tetraploid clones can easily and effectively be maintained by vine cutting for advanced uses.Plants 2020, 9, 370 2 of 16 are edible after cooking. Usually, each fruit contains more than 20 seeds and becomes harder at 3-4 weeks after pollination (Figure 1). At this point, it loses consumer acceptance because of its unpalatable seeds with hard coats. Parthenocarpy induction approaches might be able to solve this problem.The induction of parthenocarpy by exogenous plant growth regulators has already been reported for pointed gourd [2] and other cucurbits [3][4][5]. However, this practice is not genetically stable or economically feasible because it involves extra investment in labor and chemicals every year. Another approach to manage this problem is to develop triploid clones after crossing between tetraploid and diploid parents. From a horticultural point of view, such triploids are expected to be superior to their diploid counterparts, with a higher yield, more vigorous growth, and seedlessness or less-seeded characteristics, making them more attractive to consumers [6]. It has been reported that a tetraploid pumpkin fruit's weight is 2.9 kg with fewer seeds (30), while that of diploids is 2.2 kg with more seeds (122) [7]. However, this technique is restricted for seed propagated species due to the inherent difficulties in maintaining genetic stability, as well as their low rate of viable seed production [8]. However, this seedlessness strategy does not affect the commercial utility and multiplication of pointed gourd because of vegetative propagation by vine cutting. It is hypothesized that colchicine treatment might be effective in inducing tetraploids in ...

Variations in the dormancy and early flowering ability of seedlings of four populations of Lilium longiflorum, Yaku Shima (LYA), Kikai Jima (LKI), and Ishigaki Jima (LIS) in the Ryukyu Archipelago, Japan and Pitouchiao (LPI), Taiwan, and two populations of L. formosanum, Wulai (FWU), Taiwan and a domesticated Fukuoka population (FFU), Japan were investigated. Seedlings of each population were grown at 15°C for five months. They were then transplanted into an experimental open field for two years or at 15, 20, 25, and 30°C under natural day length for 22 weeks. In the field experiments, FWU, FFU, and LPI populations continued to develop new leaves even at >30°C. Flowering percentage for FFU and LPI was 90% and 19.7%, respectively. Leaf development of LIS, LKI, and LYA was completely arrested from early June in both years, and the flowering percentages were 28, 25, and, 10 in the second year, respectively. Under controlled temperature conditions, LKI and LYA populations produced new leaves only at 15°C. FFU and LPI continued growing at 25 and 30°C, whereas the other populations did not grow. FFU significantly produced the heaviest leaves and bulbs and the highest number of scales per bulb at any temperature. The results showed that high temperature induces bulb dormancy in northern L. longiflorum. Strong correlation with the early flowering ability and bulb dormancy was also found. It seems that the early flowering ability of L. formosanum is largely dependent on the lack or reduction of bulb dormancy after adaptation to the local southern climate. The latitudinal variation of this trait demonstrated the geographic gradient during species habituation in the Ryukyu Archipelago.

Several kinds of double-flowered cultivars have been produced from spontaneous mutants in Cyclamen persicum Mill. The morphology and number of organs in double flowers were investigated, and were categorized into three types: "petaloid-stamen type", "petaloid-sepal type", and "extra petals in whorl 2 type". Morphological observations showed that petaloid mutations of stamen and sepal did not appear together within an individual. In addition, three types of AG-like gene were isolated from single and petaloid-stamentype double-flower buds, and expressions in each whorl were compared. All AG-like genes were expressed in whorl 3 of single flowers, but not in that of petaloid-stamen-type double flowers. In whorl 4, although expressions of the three types of AG-like gene were observed in both single and double flowers, the expression of double flowers was lower than that of single flowers. These results suggest that naturally occurring double flowers of cyclamen can be explained by the ABC-model, and it is suspected that petaloidy of the stamen is caused by the repression of AG-like gene expression in whorl 3.

This study was conducted to demonstrate the seasonal change of floral organ number and morphology, and the effect of growth temperature on floral morphology in double-flowered cyclamen with petaloid-stamens. In plants grown under seasonal variable temperature, floral organ number and morphology in petaloid-stamen type of double flower changed as time passed, but the degrees of such changes differed depending on the line; there were two types, namely, "variable" and "relatively stable", in terms of the number of outer and inner petaloid-stamens throughout the flowering period. In the plants grown under different constant temperatures, the rate of complete petals (petaloid-stamens) to the total organs in whorl 3 was greatest at 15°C, followed by the values at 25°C and 20°C. In contrast to complete petals, the rate of incomplete petals (petaloid-stamens) to the total organs in whorl 3 was greatest at 20°C, followed by the values at 25°C and 15°C. The rate of stamenlike organs to the total organs in whorl 3 did not differ significantly among treatments, and the rate of stamens to the total organs in whorl 3 was suppressed only at 25°C. Although the total numbers of stamens and stamen-like organs were similar at 15°C and 20°C, the developed positions of stamen-like organs and stamens were significantly different between 15°C and 20°C. Additional organs including stamens were produced inside the petaloid-stamen at 15°C, while restoration of the stamen was induced at 20°C. In conclusion, floral morphology shows seasonal change, and growth temperature affects the petaloidy of stamen in doubleflowered cyclamen. However, the effect on petaloidy differs according to the line.

The very young seedlings of trifoliate orange, and its hybrids with trifoliate leaves as a marker, are usually used as a rootstock for in vitro and in vivo micrografting of citrus to eliminate viruses in spring in temperate regions. In tropical and subtropical regions or in summer, however, the production and use of trifoliate orange seedlings is difficult. Therefore, it is necessary to establish suitable micrografting using efficient Citrus seedlings adapted to these regions and summer. In decapitated seedlings for micrografting, adventitious shoots on the cut end of the epicotyls and shoots from cotyledon axillary buds are often formed. Hence, the potential for adventitious shoot formation and cotyledon axillary shoot formation was firstly studied with decapitated seedlings from 11 Citrus accessions and one Poncirus accession as a control. Mature seeds of the 12 accessions were germinated in vivo and seedlings of various ages (2-, 4-, and 8-week-old, 4-month-old and 8-month-old after germination) were decapitated at three (lower, middle, and upper) positions on the epicotyls. Adventitious shoot formation decreased with increases in the age of seedlings decapitated at eight weeks or 4 months after germination. The percentage of decapitated seedlings forming adventitious shoots was different in different accessions ranging from 0% to 100%, and increased with increases in decapitation height in the epicotyls. It was estimated from these results that 2-week-old seedlings of Natsudaidai, Shiikuwasha, 'Hiradobuntan', 'Variegated Daidai', and trifoliate orange 'Flying Dragon' had higher potential to support the initial growth of adventitious shoots, and cotyledon axillary shoots than the others, and that decapitation at the upper one-third and middle of epicotyls resulted in higher adventitious shoot formation than the lower one-third. In in vivo micrografting of satsuma mandarin on the seedlings of these accessions, Natsudaidai, 'Hirado-buntan', and 'Variegated Daidai' seedlings resulted in high micrografting success rates, whereas 'Kabusu', 'Flying Dragon' and Shiikuwasha seedlings resulted in very low success rates. The success rate decreased with increases in seedling age. It has become clear from these results that there is no relationship between the potential for shoot formation and micrografting success and that the 2-week-old seedlings of Natsudaidai, 'Hirado-buntan' and 'Variegated Daidai' are efficient rootstocks for micrografting.

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