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Vi Nguyen Tuong Do, Shan-Te Hsu and Yung-I Lee

The aim of this study was to develop an efficient protocol for shoot tip culture from adult plants of Paphiopedilum Pfitzer. A considerable seasonal effect on explant collection was observed in the aseptic cultures established from adult plants, including the survival and microbial contamination of explants. The shoot tip explants excised from adult plants in February and May showed higher survival and had less contamination than those explants excised in August and November. Moreover, the season of explant collection also affected the subsequent shoot forming capacity and multiplication of axillary buds. In Paphiopedilum ‘In-Charm Silver Bell’, higher shoot forming capacity was observed in February and May, whereas higher shoot multiplication was observed only in February. In Paphiopedilum ‘Hsinying Maudiae Leopard’, both February and May were optimal timing for shoot forming capacity and multiplication. We also demonstrated the effectiveness of transcinnamic acid (tCA), an antiauxin chemical in diminishing the apical dominance of shoot tip explant and thus improving the axillary bud outgrowth. In P. ‘In-Charm Silver Bell’, the addition of 100 μM tCA plus 13.3 μM 6-benzylaminopurine (BA) for 1 month promoted axillary shoot bud formation from shoot tip explants as compared with the control.

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John Rojas, Julian Quintero, Yhors Ciro and Javier Silva

The global annual production of shrimp is nearly 4.8 million metric tons, generating almost half this weight in waste. The aim of this study was to assess the development and crop production of legumes fertilized with alkaline sonicated shrimp waste under greenhouse conditions. Plants were grown separately under the following fertilization regimes: untreated soil, untreated cotton substrate, two commercial fertilizers [commercial organic fertilizer (COF) and commercial synthetic fertilizer (CSF)], and shrimp waste having hydrolysis degrees of 0%, 15%, 18%, and 25%. Electrical conductivity of shrimp-based fertilizers (SBFs) decreased with hydrolysis degree. However, pH (6.7–6.9), densification (0.2–0.3 g·cm–3) and conductivity (10–21 µS·cm–1) of soil was unaffected by fertilization. Furthermore, CSF had the greatest ionic exchange capability. Sonolysis resulted in an assimilable source of C, N, and O, mainly derived from carbohydrates and proteins, and increased the availability of minerals such as Ca and phosphate. The greatest plant growth in both legumes was achieved when treated with CSF, whereas the raw shrimp waste caused a beneficial plant growth and crop yield mainly for Phaseolus vulgaris. All fertilizers showed typical type II isotherms, and soil substrate per se exhibited the largest water uptake. The soil microbiota increased during the growing cycle and then decreased as the reproductive phase started. In fact, soil planted with Phaseolus vulgaris showed a greater microbial population than Pisium sativum. These shrimp waste hydrolysates can be used as alternative organic soil fertilizers and are suggested as substitutes for synthetic fertilizers.

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Celina Gómez, Christopher J. Currey, Ryan W. Dickson, Hye-Ji Kim, Ricardo Hernández, Nadia C. Sabeh, Rosa E. Raudales, Robin G. Brumfield, Angela Laury-Shaw, Adam K. Wilke, Roberto G. Lopez and Stephanie E. Burnett

The recent increased market demand for locally grown produce is generating interest in the application of techniques developed for controlled environment agriculture (CEA) to urban agriculture (UA). Controlled environments have great potential to revolutionize urban food systems, as they offer unique opportunities for year-round production, optimizing resource-use efficiency, and for helping to overcome significant challenges associated with the high costs of production in urban settings. For urban growers to benefit from CEA, results from studies evaluating the application of controlled environments for commercial food production should be considered. This review includes a discussion of current and potential applications of CEA for UA, references discussing appropriate methods for selecting and controlling the physical plant production environment, resource management strategies, considerations to improve economic viability, opportunities to address food safety concerns, and the potential social benefits from applying CEA techniques to UA. Author’s viewpoints about the future of CEA for urban food production are presented at the end of this review.

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Fan Cao, Xinwang Wang, Zhuangzhuang Liu, Yongrong Li and Fangren Peng

Pecan cuttings are difficult for rooting. This study describes the pecan hardwood rooting process based on anatomic characteristics to understand root formation mechanisms of pecan cuttings. The expressed proteins of different periods during the adventitious rooting process of pecan seedling hardwood cuttings were identified and analyzed to evaluate the rooting mechanism. The expressed proteins of pecan cutting seedlings were also compared with other cultivar cuttings during the rooting period. Pecan seedling cuttings were developed at different air and substrate temperatures to induce root formation. Adventitious root formation of pecan hardwood cuttings was described, and the phloem at the base of the prepared cuttings was selected as the sample for the differential protein analysis. The results showed that adventitious root formation of pecan hardwood cuttings was the only product of callus differentiation, which originated from the cells of the cambium or vascular ray parenchyma. Such adventitious root primordia were developed from those calluses that formed the regenerative structure, and the expressed proteins during the adventitious rooting of pecan hardwood cutting were identified and analyzed by matrix-assisted laser desorption ionization–time of flight–mass spectrometry (MALDI-TOF-MS) to evaluate the rooting mechanism. Eight differentially expressed proteins were found in the rooting periods, and 15 differential proteins were found by comparing pecan cutting types, which were analyzed by peptide mass fingerprinting homology. The results show that the primordial cells were differentiated from the meristematic cells. Furthermore, the differentially expressed proteins contained energy metabolism proteins, adversity stress proteins, and signal transmission proteins. The energy metabolism-related proteins were adenosine triphosphate (ATP) synthase, photosynthesis-related proteins, and enolase. The adversity-stress proteins containing heat shock-related proteins and signal transmission proteins were mainly cytochrome enzymes and heme-binding proteins. Adventitious root formation of pecan cultivar hardwood cuttings was difficult. More trials should be performed from the potential aspects of high defensive protection and phloem morphologic structure.

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Lumariz Hernandez Rosario, Juan O. Rodríguez Padilla, Desiree Ramos Martínez, Alejandra Morales Grajales, Joel A. Mercado Reyes, Gabriel J. Veintidós Feliu, Benjamin Van Ee and Dimuth Siritunga

The Solanaceae family is one of the largest and well-distributed plant families in the world. It contains species of agricultural and economical importance, such as Solanum tuberosum, Solanum melongena, Solanum lycopersicum, Nicotiana tabacum, and Capsicum annuum. In Puerto Rico, there are ≈46 species of Solanaceae of which six are endemic: Brunfelsia densifolia, Brunfelsia lactea, Brunfelsia portoricensis, Goetzea elegans, Solanum ensifolium, and Solanum woodburyi. Our objective was to use DNA barcoding to identify the Solanaceae species in Puerto Rico, including the endemics, and to assess the species relationships between them. To accomplish our objective, two chloroplast regions (psbA-trnH and matK) and a nuclear region [internal transcribed spacer (ITS)] were assessed. Pairwise distance and phylogenetic analysis demonstrate that DNA barcoding can be used to discriminate at the species level among these taxa in Puerto Rico. For all three markers, the genus that showed the highest pairwise distance between represented species was Solanum, whereas the genus that displayed the least was Capsicum. Phylogenetic trees of single and concatenated regions were generated from sequences obtained in this study and from data downloaded from the National Center for Biotechnology Information database. Our results show that this technique can be used to identify species with one, two, or three combinations of DNA barcode markers depending on the taxon. In addition, this is the first study to include the endemic species S. woodburyi in a molecular phylogenetic analysis, and it was found to have a close relationship with S. ensifolium, also endemic to Puerto Rico, and to Solanum bahamense from the Bahamas and Greater Antilles. Therefore, we suggest that S. woodburyi might be part of the Bahamense clade.

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Maksut Barış Eminoğlu, Uğur Yegül and Kamil Sacilik

In this study, blackberry fruits were dried in a pilot-scale hot-air dryer to identify the drying characteristics of the fruits. The air velocity was set as 1 m·s−1, and the temperature range was set as 54 to 75 °C. Fick’s law of diffusion was used to describe heat transfer during the decreasing rate period. Effective diffusivity values were calculated, and the Arrhenius constitutive model was used to describe the temperature dependence of these values. The Page, logarithmic, approximation of diffusion, two-term, and Midilli et al. models were used to fit the experimental data. A nonlinear regression analysis was used to calculate rate constants and model coefficients. The present findings revealed that among the tested models, the Midilli et al. model best described the experimental data; therefore, it was concluded that the model could be used to describe the drying characteristics of blackberry fruits.

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Shichao Wang, Zhujun Chen, Jun Man and Jianbin Zhou

In China, greenhouse soils often receive large rates of different manures and have a high content of soil organic matter (SOM). Understanding changes in nitrogen (N) mineralization in soils of newly built greenhouses after their construction is important for managing N. Soil samples were obtained from solar greenhouses of different ages (0, 1, 2, and 3 years) located in the south edge of the Loess Plateau, China, at 0- to 20- and 20- to 40-cm depth. N mineralization in the soils was measured with the Stanford and Smith long-term aerobic incubation method over 30 weeks. SOM, total N, and the mineralized N in the 0- to 20-cm and 20- to 40-cm soil layers were significantly increased in the older greenhouses. The cumulative mineralized N in the 0- to 20-cm soil layer in different cultivation years was increased in each year since the greenhouses were established. For the greenhouses with the same age, the cumulative mineralized N in the 0- to 20-cm soil layer was greater than that in the 20- to 40-cm layer. The potentially mineralizable N (N0) both in the 0- to 20-cm and the 20- to 40-cm soil layers increased with the greenhouses’ age. Regression analysis indicated that when SOM increased 1 g·kg−1, N0 in the 0- to 20-cm and 20- to 40-cm depth increased 22.6 and 8.4 mg·kg−1, respectively. Therefore, as the N supply in soil increases with the age of the solar greenhouse, we suggest that the application rates of manure and synthetic fertilizer be reduced.

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Mingtao Zhu, Jun Yu, Sheng Wu, Meijun Wang and Guoshun Yang

Spine grape (Vitis davidii Foex) is an important wild plant species in South China. To provide economical and environmentally safe ways to promote the precocious maturation of spine grape berries, the effects of riboflavin were investigated. Riboflavin affected the reactive oxygen species metabolism in spine grape berries by increasing superoxide radical production and the hydrogen peroxide content, and it impaired the activities of the antioxidant enzymes superoxide dismutase and catalase. Riboflavin also induced the upregulated expression of maturation-related genes in advance, and the earlier accumulation of anthocyanin and total soluble solids. Phenological observations revealed that the treated grape berries underwent a color-turning stage 9 days earlier than the control, and the maturation stage occurred 7 days earlier than the control. Thus, riboflavin may significantly promote the precocious maturation of spine grape berries.

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Jenny L. Bolivar-Medina, Camilo Villouta, Beth Ann Workmaster and Amaya Atucha

The formation and development of floral meristems is key to fruit production. However, limited information regarding the development of floral buds during the dormant period of cranberry (Vaccinium macrocarpon) constrains the ability to forecast yield early and accurately. The objectives of this study were to characterize the development of floral meristems from fall to spring and to evaluate the number of floral meristems formed across different bud sizes and upright types, as well as their contribution to the fruit production of the next year. Apical buds of different sizes on vegetative and fruiting uprights were tagged and collected periodically from fall to spring for histological study. An extra set of tagged buds was left in the field to evaluate their flower and fruit production. Five stages of floral development were identified based on the concentric differentiation of organ primordia. Large buds from vegetative uprights developed earlier, had a higher number of floral meristems, and became fruiting uprights; they had the highest number of flowers and fruit. Buds from fruiting uprights had the lowest number of floral meristems and delayed development; subsequently, they had the lowest number of fruit per upright. Our results provide evidence of active floral meristem differentiation during fall and winter, as well as differences in the timing and development stage according to bud size. In addition, our study shows that upright types and bud sizes influence the fruit production of the following year; therefore, they should be considered in cranberry crop forecasting models.

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Shuang Jiang, Haishan An, Xiaoqing Wang, Chunhui Shi, Jun Luo and Yuanwen Teng

Simple sequence repeats (SSRs) are widely used in cultivar identification, genetic relationship analysis, and quantitative trait locus mapping. Currently, the selection of hybrid progeny plants in molecular marker-assisted breeding mostly relies on SSR markers because of their ease of operation. In Pyrus, a large number of SSR markers have been developed previously. The method to identify polymorphic SSRs quickly is still lacking in cultivated as well as wild pear species. We present a large number of polymorphic SSRs identified using a quick in silico approach applied across 30 cultivated and wild accessions from Pyrus species. A total of 49,147 SSR loci were identified in Pyrus, and their genotypes were evaluated by whole-genome resequencing data of 30 Pyrus accessions. The results show that most SSR loci were dinucleotide repeat motifs located in intergenic regions. The genotypes of all SSR loci were revealed in all accessions. A total of 23,209 loci were detected, with more than one genotype in all Pyrus accessions. We selected 702 highly polymorphic SSR loci to characterize the pear accessions with an average polymorphism information content value of 0.67, suggesting that these SSR loci were highly polymorphic. The genetic relationship of Pyrus species in the neighbor-joining (NJ) tree and population structure showed a clear division between the oriental and occidental accessions. The population structure split all oriental pears into two groups: cultivars and wild accessions. These new findings of the polymorphic SSR loci in this study are valuable for selecting appropriate markers in molecular marker-assisted breeding in Pyrus.