Plants with the flower color phenotype of double-color flowers are very precious and attractive and can usually be regarded as valuable germplasm resources for studying and improving flower color. This paper summarizes the coloring mechanism of double-color flowers in plants from three aspects: the formation of double-color flowers, the physiological factors affecting the coloring difference of double-color flowers, and the molecular mechanism affecting the coloring difference of double-color flowers, to provide a theoretical reference for the in-depth study of the coloring mechanism and molecular breeding of double-color flowers in the future.
Xinpeng Zhang, Zongda Xu, Wenli Wang, Deyu Mu, Xiang Meng, Min Lu, and Cheng Li
Connor Bolton, Miguel Cabrera, Mussie Habteselassie, Daniel Poston, and Gerald Henry
The incorporation of biostimulants, including microbial inoculants, into turfgrass management programs has increased during the past decade as a result of the potential benefits of their use, including increased nutrient uptake, enhanced growth, and improved stress tolerance. However, minimal research has been conducted on warm-season grasses, and questions still exist regarding microbial inoculant application timing, frequency of inoculation, and need for supplemental nitrogen. Therefore, the objective of our research was to investigate the influence of nitrogen fertilizer and microbial inoculant application timings on the establishment of common bermudagrass [Cynodon dactylon (L.) Pers.] in the field and in a controlled environment. Treatments containing fertilizer had a consistently greater normalized difference vegetation index, turfgrass color, and turfgrass quality than treatments that contained only the Klebsiella variicola microbial inoculant (KV). Establishment of bermudagrass plots in response to treatments containing fertilizer had more than 90% cover at the conclusion of the study (8 weeks after seeding), whereas KV treatments and the untreated check never exceeded 70% cover. However, the greatest change in carbon efflux was often observed in the field in response to treatments that supplied KV 3 weeks after seeding. In the greenhouse, the greatest root and shoot weights were typically observed in response to treatments containing fertilizer, whereas KV-alone treatments resulted in root and shoot weights either similar to or less than the untreated check.
Young-Sik Park, Je-Chang Lee, Nam-Yong Um, Haet-Nim Jeong, and Jae-Yun Heo
In Korea, ‘Campbell Early’, ‘Shine Muscat’, and ‘Kyoho’ account for more than 90% of the Korean grape cultivation area (
John Berkomah, Haiwen Li, Rafat Siddiqui, Chyer Kim, and Harbans Bhardwaj
This student-led project studied the production of cilantro (greens stage) and coriander (seed stage) of Coriandrum sativum L. with the objective of developing this crop as an alternate specialty crop in Virginia. Results indicated that both fall-planted for spring harvest and spring-planted for summer harvest are possible in Virginia. Rows spaced 37.5 cm apart resulted in the superior yield of both cilantro and coriander over rows 75 cm apart. Mean cilantro fresh yields from fall-planted experiments (three cultivars during 2015 and five cultivars during 2016) varied from 3301 to 5775 kg⋅ha−1, whereas those from spring-planted experiments varied from 4971 to 11811 kg⋅ha−1. Corresponding values for dry cilantro yields varied from 274 to 1129 kg⋅ha−1 and 862 to 2280 kg⋅ha−1, respectively. Mean coriander seed yields from three fall-planted cultivars varied from 818 to 1554 kg⋅ha−1, and those from three spring-planted cultivars varied from 869 to 1277 kg⋅ha−1. The total phenolic content in cilantro was significantly greater than that in coriander seed (4.95 and 1.15 g of gallic acid equivalent per 100 g of material, respectively). The total mesophiles, yeast and mold, and coliforms from three grocery store-bought cilantro were considerably higher than those of greenhouse-grown cilantro. Even though both spring and fall plantings are possible for supplying cilantro in Virginia, fall planting for spring harvest might be more profitable for producers because of the earlier availability of locally grown cilantro.
Shoufu Gong, Bailing Miao, and Xiangxiang Dong
Gardenia jasminoides, belonging to the Rubiaceae family, is widely distributed and planted in China. It has traditionally been used as an ornamental and medicinal plant in several Asian countries. The rapid development of high-throughput sequencing technology makes it feasible to obtain complete chloroplast (cp) genome sequences and will deepen our understanding of evolution of G. jasminoides. In this study, we sequenced the complete cp genomes of two botanical varieties of G. jasminoides. The complete cp genomes of both botanical varieties of G. jasminoides showed highly conserved structures and the length was 154,954 base pairs (bp) for G. jasminoides var. radicans (GJR) and 155,098 bp for G. jasminoides var. grandiflora (GJG). A total of 132 and 133 genes were identified in GJR and GJG, respectively. The cp genomes of two newly sequenced G. jasminoides were further compared with two published G. jasminoides cp genomes. Multiple repeats and simple sequence repeats (SSRs) were detected among different genotypes of G. jasminoides. The intron sequences of rps16 and rpl16 genes were slightly divergent among four genotypes of G. jasminoides. Phylogenetic analyses based on the complete cp genome sequences showed that G. jasminoides was closely associated with Fosbergia shweliensis, with Coffea as their close relative. Taken together, the complete cp genomes of GJG and GJR provided significant insights and important information that can be used to identify related species and reconstruct their phylogeny.
Andrew Mullin, Bárbara Nogueira Souza Costa, Jason Downing, and Amir Ali Khoddamzadeh
Florida is home to 106 native orchid species, of which 77 are listed as endangered or threatened by the State of Florida. The Institute for Regional Conservation (IRC) has classified 62 of these species as either critically imperiled, imperiled, or rare in South Florida. Because of lack of endosperm, orchid germination rates are very low in nature, as they depend on an obligate relationship with mycorrhizal fungi for nutrients. Most orchid seeds can be germinated in vitro without the need for specific mycorrhizal fungi. This study aims are to establish a fast and efficient protocol for in vitro seed germination using different nutrient media and plant growth regulator (PGR) combinations, and to optimize seedling acclimatization protocols using different greenhouse media. To determine germination preferences, three different in vitro seed germination media were tested supplemented with PGRs, including 1) Murashige & Skoog (MS) (control), 2) MS supplemented with 1.5 mg/L 6-benzylaminopurine (BAP), and 3) MS supplemented with 1 mg/L BAP and 0.5 mg/L 1-Naphthaleneacetic acid (NAA) on Cyrtopodium punctatum, a state-listed endangered, IRC critically imperiled epiphytic orchid. There was no significant difference amongst the treatments after 2 and 6 weeks of seed sowing culture. To understand post-culture survivorship, two epiphytic and one terrestrial native species (Trichocentrum undulatum, Encyclia tampensis, and Oncidium ensatum) were chosen for the acclimatization study with two commercially available potting substrates (coir, sphagnum). To measure seedling growth rates, phenotypic measurements [leaf number, leaf length, root length, plantlet height, light intensity, pH, and electrical conductivity (EC)] and Soil Plant Analysis Development (SPAD) and Normalized Difference Vegetation Index (NDVI) values were recorded monthly for five months. All media/PGR combinations resulted in an initial high percentage of stage I growth but inhibited Protocorm-like bodies (PLBs) development, suggesting more research is necessary to determine later improvements or detriments to MS basal media with BAP and NAA. Comparing acclimatization media with the three species of orchid chosen for this experiment, neither O. ensatum nor E. tampensis showed a marked preference for sphagnum moss or coir. However, T. undulatum did perform better with coir compared with sphagnum. This research will help botanical gardens and commercial plant tissue culture laboratories to have a better understanding on selection of PGR combinations for in vitro cell culture and acclimatization media on increasing the viability and plant health and decreasing the mortality of endangered plants.
S. Brooks Parrish and Zhanao Deng
Cultivated caladium (Caladium × hortulanum; 2n = 2x = 30) is an important ornamental aroid for the environmental horticulture industry. A better understanding of its genetic diversity is needed for continued improvement of caladium. The caladium germplasm maintained in the University of Florida’s caladium breeding program were surveyed for potential variation in chromosome number and nuclear DNA content to gain a better understanding of caladium genetic diversity at the cytogenetic level. For the first time caladium triploidy was discovered in two breeding lines, UF-15-414 and UF-4407 with 2n = 3x = 45 chromosomes and a nuclear DNA content of 13.86 pg·2C−1. In addition, a new chromosome number (2n = 2x = 34) was found in one cultivar, ‘White Wing’. Compared with their diploid parents or grandparents, the triploids showed a distinct, attractive leaf morphology with rounder and thicker leaves. The pollen stainability of UF-15-414 and UF-4407 was 63% and 73%, respectively, indicating potential male fertility, which was unexpected. Analysis of simple sequence repeat (SSR) marker banding patterns confirmed that UF-15-414 was a direct progeny of UF-4407 through hybridization with the diploid cultivar Aaron, whereas UF-4407 might result from fusion of an unreduced (female or male) gamete with a reduced gamete. Chromosome counting and SSR marker analysis of ‘White Wing’ and its progeny cultivars ‘White Wonder’ and ‘White Delight’ suggested that ‘White Wing’ possibly transmitted its 34 chromosomes to progeny during sexual reproduction. The discovery and characterization of these triploids revealed the occurrence of natural sexual polyploidization in caladium and indicated good potential for creating and selecting new triploids for future caladium breeding. The observed new chromosome number in ‘White Wing’ and its progeny cultivars implies that other chromosome variations may be present among cultivated caladiums. In summary, these results revealed two male-fertile triploid caladiums and a new chromosome number that can enrich the cytogenetic diversity in future caladium cultivar development.
Masaru Homma, Takafumi Watabe, Dong-Hyuk Ahn, and Tadahisa Higashide
We investigated the relationships among the fruit set, dry matter production, and source-to-sink ratio of sweet pepper (Capsicum annuum) plants grown in a greenhouse. We quantified daily fruit sink strength per stem (st) at m days after transplanting (SSTm_st) by modeling the fruit growth curve. The daily total dry matter production (TDMm_st) was calculated and defined as the source strength. During an experiment lasting ≈250 days, the fruit set ratio [number of fruit harvested/number of flowers (FSRm)] decreased significantly with increases in both the weekly average SSTm_st from 9 days before anthesis (DBA) to 13 days after anthesis (DAA) and the weekly average fruit number (FRNm_st) from 9 to 1 DBA. FSRm increased significantly with increases in both the weekly average TDMm_st from 1 to 13 DAA and the weekly average source-to-sink ratio [source strength/fruit sink strength (SSRm_st)] from 5 DBA to 13 DAA. During the whole experimental period, significant positive correlations with FSRm were observed for TDMm_st and SSRm_st, and significant negative correlations with FSRm were observed for SSTm_st and FRNm_st. FSRm increased until approximately the time when the weekly average SSRm_st at 1 to 7 DAA (anthesis to 156°C⋅d−1) ranged from 1.0 to 4.0; then, it showed a saturation curve at SSRm_st values more than 4.0 (R 2 = 0.81). These results suggest that it is possible to moderate the fluctuations in sweet pepper yield by monitoring the SSRm_st and the number of fruit set.
Xiaokai Lin, Feng Liu, Haizhi Liao, Jingjia Du, Junjie Peng, and Kaibing Zhou
To investigate the characteristics of photosynthetic physiological changes in leaves of Mangifera indica L. cv. Guifei under enhanced ultraviolet (UV)-B radiation, natural light-exposed trees were used as controls and 96 kJ·m−2·d−1 enhanced UV-B radiation was artificially simulated in the field. The changes in fruit maturity and quality, the leaf net photosynthetic rate (Pn), photosynthetic pigment contents, photochemical reactions, the activities of photosynthetic enzymes and related gene expression levels were determined. Compared with the control, the percentage of mature fruits under the treatment significantly increased, and fruit quality improved. The net photosynthetic rate (Pn), photosynthetic pigment content, Hill reaction activity, and photochemical quenching coefficient (qP) of the treated leaves showed significantly higher values than those of the control leaves. The activities of Rubisco and Rubisco activating enzyme (RCA) and the expression levels of the Rubisco large subunit and Rubisco small subunit were significantly increased. Treatment with 96 kJ·m−2·d−1 enhanced ultraviolet-B radiation improved Rubisco activity by increasing the expression of the Rubisco large and small subunit genes, thereby enhancing the CO2-fixing capacity and dark reaction capacity of leaves. Thus, the net photosynthetic rate of leaves increased, which promoted the early maturity of ‘Guifei’ mango by the rapid accumulation of photosynthetic products.
Chia Ting Han, Yu Sung, and Ming-Tung Hsueh
Seeds of some winged bean varieties have low germination due to the presence of water-impermeable hardseeds. Seeds of ‘Taitung No.1’ winged bean had only 31% germination because the remaining 69% of seeds had a water-impermeable seedcoat. Sandpaper abrasion and sulfuric acid immersion for 15 and 25 min effectively removed hardseededness of the seeds, resulting in more than 89% germination. As seed moisture content (MC) decreased from 14.8% to 7%, the percentage of seeds with a water-impermeable seedcoat increased. Seed lots with 14.8%, 11%, 9%, and 7% MC had 7%, 38%, 56%, and 78% of hardseeds, respectively, on day 7 in the germination test. It was found that the hilum was responsible for water loss from the whole seed, and the seedcoats began to become water-impermeable at 12% MC. The lens and micropylar regions were initial water entry sites in the Vaseline-blocking experiment.