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  • Author or Editor: Yan Yao x
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Phalaenopsis plants are routinely shipped long distances in total darkness. To determine how these long dark periods affect photosynthetic status in Phalaenopsis Sogo Yukidian ‘V3’, changes of net CO2 uptake, photosystem II (PS II) efficiency, and abscisic acid (ABA) concentration after a long-term simulated dark shipping were investigated. Net CO2 uptake rate, malate concentration, and titratable acidity in potted Phalaenopsis Sogo Yukidian ‘V3’ decreased after a 21-day simulated dark shipping at 20 °C, but recovered gradually with time after shipping. It took 6 to 9 days to recover to a normal photosynthetic status after shipping. The value of Fv/Fm was little affected by shipping. Therefore, net CO2 uptake rate would be a better indicator for estimating the recovery time after shipping. After shipping, fresh weight loss, leaf ABA concentration, and number of yellowed leaves of bare-root plants were higher than those of potted plants, and increased with longer durations (7, 14, and 21 days) of the simulated dark period. The spiking (the emergence of flowering stems) date was delayed when plants were stored in a bare-root condition. The concentration of ABA in leaves rose in the first 3 days after simulated shipping and then decreased within the next 3 to 8 days. Plants that received photosynthetic photon flux (PPF) at 399 μmol·m−2·s−1 after shipping had lower PS II efficiency and reduced net CO2 uptake rate than those given less PPF levels. We recommend a post-shipping acclimation for 6 to 9 days with gradual light increase (34–72–140–200 μmol·m−2·s−1 PPF) or maintaining a light level of 140 μmol·m−2·s−1 PPF for Phalaenopsis to achieve a better photosynthetic status after prolonged dark storage.

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Phalaenopsis is one of the most important ornamental crops and is frequently transported between continents. In this study, the effects of the duration and temperature of simulated dark shipping (SDS) and the temperature difference between cultivation greenhouses and shipping containers on the carbohydrate status and post-shipping performance were investigated. With a prolonged SDS from 0 to 40 days at 20 °C, the percentage of the vegetative Phalaenopsis Sogo Yukidian ‘V3’ plants with yellowed leaves increased from 0% to 50%, and the total carbohydrate contents in the shoot and roots gradually decreased over time. Furthermore, roots had greater reductions in glucose and fructose concentrations than the shoot after 40 days of SDS. After 7 days of SDS, the youngest bud and the nearly open bud on blooming plants of Phalaenopsis amabilis were found to be the most negatively affected among flowers and buds of all stages. These buds had lower soluble sugar concentrations and flower longevities compared with those of unshipped plants. The results of a temperature experiment showed that yellowing of the leaves and chilling injury (CI) occurred in Phalaenopsis Sogo Yukidian ‘V3’ after 21 days of SDS at 25 and 15 °C, respectively, regardless of pre-shipping temperature acclimation. However, 10 days of acclimation at 25/20 °C (day/night) before SDS reduced CI and reduced the time to inflorescence emergence. Higher accumulations of sucrose in the shoot and glucose and fructose in roots were found after 21 days of SDS at 15 °C compared with those at 25 and 20 °C. In conclusion, the carbohydrate status of Phalaenopsis was positively related to the post-performance quality. A reduction in the commercial quality after SDS may be attributed to a decline in carbohydrates. The optimal temperature for long-term dark shipping is 20 °C, and we recommend providing 10 days of lower-temperature acclimation (25/20 °C) before shipping to enhance the chilling tolerance and to promote early spiking of Phalaenopsis plants.

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The rapid expansion of Asian populations in the United States presents significant requirements for Asian vegetables. Flowering chinese cabbage (Brassica rapa L. ssp. chinensis var. utilis Tsen et Lee) is one of the most popular vegetables in China. The main factors restricting the progress in its breeding and genetic studies is the time required in generating desired pure line populations. Doubled haploid (DH) populations of flowering chinese cabbage have not been established because of technical difficulties. An appropriate combined protocol for a fast generation cycling system could advance up to seven generations, allowing the production of pure line seeds within 336–420 days among four cultivars and one hybrid of flowering chinese cabbage. The previous six generation cycles were accelerated using the embryo culture plus soil method which bypassed seed maturation through in vitro culture of immature embryos and promoted plant reproduction under stressed conditions, then the seventh generation cycle was accomplished until mature seeds were harvested using the soil method. During the culture of immature embryos, 12-day-old embryos could germinate and develop successfully on a Murashige and Skoog medium (MS) medium () containing 10% young coconut juice. This combined protocol bypasses the current obstacles in constructing DH populations of flowering chinese cabbage and is a possible alternative for producing pure lines. Its wider adoption could facilitate the breeding and biological studies of other Brassicaceae vegetables.

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Phalaenopsis flowers are prone to wilting under ethylene (C2H4) stress. 1-Methylcyclopropene (1-MCP) can protect Phalaenopsis flowers against ethylene injury. In this study, we determined the residual effect of 1-MCP and how it is affected by temperature. The efficacy of multiple applications of 1-MCP was also investigated. The residual effect of 1-MCP was determined by pretreating blooming Phalaenopsis amabilis plants with 0.8 μL·L−1 1-MCP for 8 hours on Day 0 followed by 2 μL·L−1 ethylene fumigation for 12 hours on designated days. Without 1-MCP pretreatment, flowers began to wilt within 2 days after exposure to ethylene. Duration of the residual protection of 1-MCP on P. amabilis was ≈6 to 8 days during summer in Taiwan. Lower temperatures after 1-MCP application prolonged protection times. The full protection times under day/night temperatures of 25/20, 20/15, and 15/13 °C were 4 to 8, 10 to 13, and 13 to 17 days, respectively. Furthermore, multiple applications of 1-MCP extended the duration of 1-MCP protection against ethylene. Three applications increased the residual protection of P. amabilis by 1-MCP to at least 24 days.

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To improve plant quality and fertilizing efficiency, we conducted a study to elucidate the effects of nitrogen (N), phosphorous (P), and potassium (K) fertilizers on the growth, nutrient accumulation, and quality of Lagerstroemia indica plants grown in containers and determine the optimal fertilization levels. Both single-factor and multifactor experiments involving N, P, K fertilizers were designed. Integrated with the plant growth, physiological traits, nutrient levels, and other indices, we used a membership function analysis to comprehensively evaluate plant quality. During the single-factor experiments, the best levels of the single fertilizers applied were 8 g/plant N, 2 g/plant P, and 4 g/plant K. We also found that, within a certain range, N, P, and K fertilizers promoted vegetative growth, increased the chlorophyll, soluble sugar, and soluble protein concentrations, and enhanced nutrient accumulation of L. indica. To avoid the wasting of fertilizers and promote plant quality, the optimal application levels were calculated using a regression analysis. The suggested N, P, and K applications were 6.89 g/plant, 1.97 g/plant, and 3.33 g/plant, respectively. Our results revealed that N, P, and K effect the performance of L. indica container plants, which paves the way for developing reliable and precise fertilizing techniques for growing L. indica.

Open Access

Nuclear DNA contents were estimated by flow cytometry in 18 Phalaenopsis Blume species and Doritis pulcherrima Lindl. DNA amounts differed 6.07-fold, from 2.74 pg/diploid nuclear DNA content (2C) in P. sanderiana Rchb.f. to 16.61 pg/2C in P. parishii Rchb.f. Nuclear DNA contents of P. aphrodite Rchb.f. clones, W01-38 (2n = 2x = 38), W01-41 (2n = 3x = 57), and W01-22 (2n = 4x = 76), displayed a linear relationship with their chromosome numbers, indicating the accuracy of flow cytometry. Our results also suggest that the 2C-values of the Phalaenopsis sp. correlate with their chromosome sizes. The comparative analyses of DNA contents may provide information to molecular geneticists and systematists for genome analysis in Phalaenopsis. Endoreduplication was found in various tissues of P. equestris at different levels. The highest degree of endoreduplication in P. equestris was detected in leaves.

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Anthocyanins are protective pigments that accumulate in plant organs such as fruits and leaves, and are nutritionally valuable components of the human diet. There is thus considerable interest in the factors that regulate synthesis. Malus crabapple leaves are rich sources of these compounds, and in this study we analyzed leaf coloration, anthocyanin levels, and the expression levels of anthocyanin biosynthetic and regulatory genes in three crabapple cultivars (Royalty, Prairifire, and Flame) following various temperature treatments. We found that low temperatures (LTs) promoted anthocyanin accumulation in ‘Royalty’ and ‘Prairifire’, leading to red leaves, but not in ‘Flame’, which accumulated abundant colorless flavonols and retained green colored leaves. Quantitative reverse transcript PCR (RT-PCR) analyses indicated that the expression of several anthocyanin biosynthetic genes was induced by LTs, as were members of the R2R3-MYB, basic helix–loop–helix (bHLH) and WD40 transcription factor families that are thought to act in a complex. We propose that anthocyanin biosynthesis is differentially regulated in the three cultivars by LTs via the expression of members of this anthocyanin regulatory complex.

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