Angelonia (Angelonia angustifolia) is an important potted flowering plant or bedding plant widely used in tropical and subtropical regions. However, most Angelonia cultivars have relatively small flowers and demonstrate limited drought tolerance in root-restricted environments such as small containers. Polyploid plants often exhibit larger flowers and enhanced drought tolerance. In this study, Angelonia ‘Serena White’ seeds and ‘Serena Purple’ seedlings were treated with 0.1% and 0.2% colchicine to induce polyploid lines, respectively. The resulting tetraploids had larger pollen and flowers, along with thicker, greener leaves distinguished by serrated edges, longer stomata, and lower stomatal density compared with diploid ‘Serena White’ and ‘Serena Purple’ plants. Both diploid and tetraploid plants subjected to a 20% volumetric water content (VWC) treatment exhibited smaller leaves, higher SPAD-502 readings, and a decreased number of flowers compared with those subjected to 40% VWC treatment. Moreover, tetraploids had higher photosynthetic rates than diploids under both 20% and 40% VWC conditions. When grown in 0.8-L containers, tetraploid plants required fewer watering events and had thicker, erect stems with larger flowers than diploids, even under a 20% VWC treatment. Colchicine-induced polyploidization presents a promising method to potentially enhance drought tolerance in angelonia.
Based on the International Camellia Register (ICR), an analysis of 1616 cultivars of Sasanqua that were registered in 2022 and earlier was conducted. This analysis focused on the resource and biological characteristics of the cultivars. Additionally, a trait diversity analysis, principal component analysis, and cluster analysis of 118 cultivars that had complete morphological records were performed. The findings revealed a rich diversity of Sasanqua cultivars, with Japan, the United States, and Australia being the main sources. The primary flower color was red, followed by multiple colors, white, and rare colors. The predominant flower forms were single-petal and semi-double-petal, with a limited number of formal double-petal forms. Elliptical leaf shapes were the most common, and the predominant leaf colors were green and deep green. The flowering period mainly corresponded to early flowering cultivars. The phenotypic diversity index (H) of the 118 cultivars ranged from 0.31 to 1.84. The flower diameter exhibited the highest H value (1.84), whereas leaf shape had the lowest H value (0.31). The coefficient of variation (CV) ranged from 21.67% to 71.81%, with the flower diameter having the smallest CV (21.67%) and petal number having the largest CV (71.81%). The first three principal components, which accounted for a cumulative contribution rate of 62.49%, effectively represented most of the information regarding the seven trait indicators of the different cultivars. Furthermore, a cluster analysis was conducted based on the flower form, diameter, petal numbers, and other characteristics of the various cultivars. The 118 cultivars were divided into three groups. The first group could be used for breeding single-petal flower cultivars, whereas the third group exhibited a larger number of petals and could be used for breeding double-petal flower cultivars.
Zebra-stem of tomato is a disorder characterized by leaf necrosis, wilting, and a stripped pattern on stems of mature plants. Wilting, necrosis, and death of seedlings are also observed. The physiological and genetic causes of zebra-stem are poorly characterized. Anecdotal evidence has suggested pedigrees with S. pimpinellifolium and bacterial speck resistance in the genetic background are often prone to this disorder. We demonstrate a genetic cause using composite interval mapping and association analysis approaches to define quantitative trait loci (QTLs) that contribute to the disorder. A biparental population of F4 partially inbred families was developed for the initial analysis, and four subsequent backcross or F2 populations were used for subsequent validation. Significant QTLs on chromosomes 5 and 10 were identified, explaining ∼60% and 40% of the variation, respectively. Polymorphisms in the Pto locus are strongly associated with the QTL on chromosome 5. The two loci were derived from different parentage, and a significant interaction effect was demonstrated, resulting in the characteristic zebra-stem symptoms when combined.
There is a growing trend toward planting native and pollinator-friendly plants in residential gardens and landscapes due to concerns about invasive plant species, water conservation, and urban land management. Yet, understanding consumer purchase behavior and how knowledge affects their purchase intent is largely unknown. In this analysis, we integrated national online and in-person surveys to determine the influence of consumers’ subjective and objective knowledge of native and pollinator-friendly ornamental plants on their purchase decisions. Factors influencing plant purchase decisions were measured using a 7-point Likert rating scale. We found that participants with relatively higher knowledge of native and pollinator-attractive plants placed more emphasis on sustainable production methods relative to the plant’s physical attributes (e.g., plant size, shape, etc.) and care-related characteristics (e.g., plant health, easiness of care, etc.). Plant lovers (i.e., frequent purchasers who spent relatively more money on plants than infrequent purchasers) were more likely to prioritize sustainable production methods over the plants’ physical attributes. In contrast, participants primarily buying plants from mass merchandisers/box stores tend to focus on visual appeal or aesthetic characteristics. Consumer marketing implications for the nursery and greenhouse industry stakeholders are discussed.
The effects of sole-source lighting on the growth and yield of hydroponically grown lettuce have been extensively studied, but research of postharvest performance is limited. We grew frill-leaf lettuce (Lactuca sativa) ‘Green Incised’ and ‘Hydroponic Green Sweet Crisp’ hydroponically in an indoor vertical research farm under daily light integrals (DLIs) of 12 or 18 mol⋅m−2⋅d−1 and the following three ratios of blue (B; 400–499 nm) and red (R; 600–699 nm) light from light-emitting diode fixtures: B5:R95, B20:R80, and B35:R65. We postulated that biomass accumulation would increase with the DLI and decrease with the B light fraction, and that postharvest longevity would increase with the DLI and the B light fraction. As expected, shoot fresh weight, leaf length and width, leaf number, and relative chlorophyll content (SPAD; ‘Green Incised’ only) decreased as the proportion of B light increased from 5% to 35%. Decreasing the DLI from 18 to 12 mol⋅m−2⋅d−1 reduced the shoot fresh weight and leaf number of both cultivars. Leaves of ‘Green Incised’ were up to 27% wider under B5:R95 and 60% longer under B5:R95 at 12 mol⋅m−2⋅d−1 than those under treatments with a higher DLI or more B light. The shoot fresh weight of ‘Hydroponic Green Sweet Crisp’ was greatest when grown under B5:R95 at 18 mol⋅m−2⋅d−1 and decreased as B light increased or DLI decreased. At the time of harvest, leaves of each cultivar and treatment were placed in clamshells and stored at 7 °C in darkness and evaluated for decay. ‘Green Incised’ that grew under B35:R65 and a DLI of 18 mol⋅m−2⋅d−1 had the shortest storage life, with 9.5 d and 11.4 d for replications 1 and 2, respectively, which were ∼2.5 to 4.0 d and 1.4 to 3.6 d earlier, respectively, than the storage life of lettuce grown under other treatments. In contrast, ‘Hydroponic Green Sweet Crisp’ was not influenced by light quality or DLI and had a storage life of 12.6 to 13.3 d and 13.5 to 14.3 d for replications 1 and 2, respectively. Therefore, a B light fraction between 5% and 20% and a DLI of 18 mol⋅m−2⋅d−1 produced high-yielding frill-leaf lettuce with a relatively long storage life.
Violets (Viola) are potential candidates for aroma-focused breeding research. Though most Viola species and modern hybrids lack fragrance, the genus contains a famously scented species, Viola odorata L. This species and its cultivars are genetic resources of aroma traits that could be used to investigate the selection for and transmission of fragrance during the breeding process. Despite its famous scent, however, the floral volatile emissions of V. odorata have not been characterized using modern headspace techniques. Using static and dynamic headspace volatile collection methods and gas chromatography–mass spectrometry, the floral volatile emissions of V. odorata were temporally and developmentally characterized. Floral volatiles were also sampled from 10 V. odorata cultivars, three Parma violet cultivars, five violet species, and one hybrid, and variation in scent among these violets was investigated. Total volatile emissions in V. odorata were highest from 0600 HR to 1900 HR, suggesting a diurnal pattern of emission. Volatile emissions also varied over the developmental lifespan of the flower, with the highest emission of individual and total volatiles occurring, in general, from stages 0 or +1 to stages +3 or +4. Floral scent qualitatively and quantitatively differed among assorted violets. The floral volatile emissions of V. odorata exhibit temporal and developmental variation. Compared with the other violet species in this study, sweet violets are intensely fragrant. The quantity and quality of floral scent differs among V. odorata cultivars, providing genetic variation from which selections could be made in a fragrance-focused breeding program.
Temporal separation of red (R) and blue (B) (alternating R/B) photons has been reported to increase leaf area, photon capture, and yield of lettuce compared with delivering both colors together (concurrent R+B). We grew three diverse lettuce cultivars (Grand Rapids, Rex, and Red Sails) under concurrent R+B photons (9/1 ratio) and alternating R/B photons (9/1 ratio) under an equal daily light integral (DLI) of either 8.6 or 23 mol⋅m−2⋅d−1. Contrary to five previous studies, we found no increase in either leaf area or fresh mass and dry mass in any of the alternating R/B photon treatments compared with concurrent R+B photons. In fact, at a DLI at 8.6 mol⋅m−2⋅d−1, alternating R/B photons decreased the dry mass of ‘Grand Rapids’ and ‘Rex’ lettuce by 38% and 17%, respectively. Two previous studies reported that photosynthetic rates increased with alternating R/B photons; however, we found that the net assimilation rate was generally decreased by alternating R/B photons. An analysis of images obtained from automated digital photography revealed that the relative expansion rate of leaves was 61% higher during intervals of pure B rather than intervals of pure R photons at the same photosynthetic photon flux density; however, this did not result in a higher leaf area compared with concurrent R+B photons. Overall, our studies do not indicate that alternating R/B photons increase lettuce leaf area or yield compared with concurrent R+B photons.
Green care activities are associated with lower intensity and a lower risk of injury than agricultural activities aimed at producing agricultural and livestock products; however, the risk of health problems cannot be completely ruled out. To implement green care interventions to improve physical health, it is essential to identify the green care activity levels and biomechanical characteristics of the movements that are appropriate for each subject’s physical functions and goals. Thus, this study was conducted to determine the muscle activation of the upper and lower limbs during 19 green care farming activities. We used electromyography signals, which are biomedical signals that measure the action potentials generated in the muscles and nervous system when the muscles contract, to evaluate the muscle activation. Twenty adults (aged 29.9 ± 9.6 years) participated in this study. Participants performed 19 green care farming activities, including horticultural activity, animal-mediated, and off-farming activities. The participants performed each activity three times. The electromyography data were assessed using surface electromyography during activities to measure muscle activation. As a result, 16 upper and lower limb muscles were activated during the green care farming activities, which showed significantly different muscle activation by care farming activity. As a result of the comparison of muscle activity according to each muscle, many of the muscles of the upper and lower limbs were most activated during organizing a garden plot, transplanting plants, and collecting natural objects. In conclusion, the electromyography data obtained during this study suggest that green care farming interventions may be effective for training specific muscles of the upper and lower limbs.