Plant Maturity Affects Flowering Ability and Flower Quality in Phalaenopsis, Focusing on Their Relationship to Carbon-to-nitrogen Ratio

In the commercial production of phalaenopsis orchids, the cultivation time after deflasking is used to describe the plant age and maturity. Carbon-to-nitrogen (C/N) ratio is often used as an indicator of plant growth and flowering potential. High C/N ratios are considered to promote reproductive growth, and low C/N ratios are associated with the early vegetative growth or even inhibiting flowering. This study investigated how plant age and maturity affected flowering ability and flower quality of phalaenopsis and their relationship to C/N ratio. The plant materials of various ages were the purple, small-flowered Phalaenopsis Sogo Lotte ‘F2510’ and white, large-flowered P. Sogo Yukidian ‘V3’, which were 2 to 7 months and 10 to 20 months after deflasking, respectively. Plants were placed under 25/20 °C for 4 months to force flowering and investigate the flowering-related parameters. The leaf C/N ratio of both varieties increased in general with the increase of plant age. The spiking (flower-stalk emergence) rate of P. Sogo Lotte ‘F2510’ 2 months after deflasking was only 42%, which indicates that these plants were not completely out of their juvenile phase, whereas that of those 3 to 7 months after deflasking was 100%, indicating that plants had acquired full flowering ability. No linear correlation was found between the C/N ratio and days to spiking, to first visible bud, to first flower open, and to 90% flower opening in the white, large-flowered P. Sogo Yukidian ‘V3’. However, there was a positive correlation between the C/N ratio and inflorescence length, flower-stalk diameter, first flower diameter, and flower count. Thus, the C/N ratio is feasible to be used as an indicator for assessing the flowering quality in phalaenopsis.

Enhance Growth and Flower Quality of Chrysanthemum indicum L. with Application of Plant Growth Retardants

Ornamental plants are cultivated worldwide. Chrysanthemum is classified as one of the most important cut and potted flowers in most of the countries. The consumer’s expectation is to find small–compact, and full of inflorescences plants. To meet these demands, growers are tending to use plant growth retardants. Three Chrysanthemum indicum L. varieties (‘Smola White’, ‘Arber’ and ‘Vienna White’) were assessed by using four plant growth regulators (PP–Bumper 250 EC; CC–Stabilan SL; MP–Medax Top SC; and PD–Toprex SC). Results indicate that treated plants show significant decrease in the assessed parameters, although in some cases growth could be a variety–dependent factor. It can also be concluded that retardants inhibit chrysanthemum growth. PD treatments greatly inhibited the growth of the plant, and also had a negative effect on inflorescences. In conclusion, the present work strengthens the possibility of using retardants as plant growth inhibitors in Chrysanthemum cultivation.

Prospects of neem and citronella oil against Pseudococcus longispinus (hemiptera: Pseudococcidae) on Phalaenopsis

Synthetic insecticides are still widely used in gardens and greenhouses of ornamental crops to reduce populations of insect pests and preserve flower quality. The improper and unwise use of synthetic insecticides has caused various negative impacts on humans, insect pests, and the environment. Therefore, the quest for unharmed insecticides and environmentally friendly is being sought. The purpose of this study was to examine the effectiveness of botanical insecticide formulation of neem and citronella oil to control long-tailed mealybug Pseudococcus longispinus. Four insecticide concentrations of neem, citronella oil and its mixtures (0.5, 1, 1.5, 2 per cent) were tested for their effectiveness by adding each with Latron at 0.5% as an emulsifier. Bioassays were performed in the laboratory by spraying insecticides on Phalaenopsis leaves infested with P. longispinus groups of one size class, mostly represented by the third instar nymphs. The results revealed that all insecticides tested caused mortality after 24 hours. The combination of neem and citronella in 1.5% provided adequate protection by reducing P. longispinus populations by up to 86%. Thus, botanical insecticides can be recommended as a viable alternative to synthetic insecticides against P. longispinus which infested orchids.

Drought and Darkness during Long-Term Simulated Shipping Delay Post-Shipping Flowering of Phalaenopsis Sogo Yukidian ‘V3’

We investigated the relationship between simulated shipping (SS) without watering or light and post-shipping growth and flowering of Phalaenopsis Sogo Yukidian ‘V3’. Two experimental environments were created: a low-temperature chamber for simulated shipping and a growth chamber for simulated finishing at the destination. Plants from both the control and treatment groups were moved from the low-temperature chamber to the growth chamber after the end of the simulated shipping. Control plants received continuous light and regular irrigation; plants in the treatment group were placed in the low-temperature chamber under light (LSS) or dark (DSS) conditions for 10, 20, 30, 40, or 50 days, without irrigation. Once DSS duration exceeded 40 days, the leaf-yellowing rate increased rapidly. Chlorophyll content decreased from day 10 to 30 of DSS and slightly increased in LSS and DSS over 40 days. The photochemical reflectance index decreased with the SS duration. The maximum quantum yield PSII photochemistry (Fv/Fm) values sharply decreased after the end of SS; after 40 days, neither LSS nor DSS plants recovered to the normal range. In the same SS duration, the number of days to spiking was delayed in the DSS. In addition, the number of days to spiking was delayed, owing to the longer SS duration. LSS for 50 days induced early flowering, as in the control group, but lowered flower quality. The results demonstrate that drought stress from long-term shipping (>40 days) delayed flowering. In particular, DSS delayed flowering more than LSS due to the decrease in chlorophyll content and the reduction in carbohydrates through respiration.

Silicon Nanoparticles Improve the Shelf Life and Antioxidant Status of Lilium

The production of ornamentals is an economic activity of great interest, particularly the production of Lilium. This plant is very attractive for its color and shapes; however, the quality of its flower and its shelf life can decrease very fast. Therefore, it is of the utmost importance to develop techniques that allow for increasing both flower quality and shelf life. Nanotechnology has allowed for the use of various materials with unique characteristics. These materials can induce a series of positive responses in plants, among which the production of antioxidant compounds stands out. The objective of this study was to determine the impact of the application of silicone nanoparticles (SiO2 NPs) on the quality, shelf life, and antioxidant status of Lilium. For this, different concentrations of SiO2 NPs (0, 200, 400, 600, 800, and 1000 mg L−1) were applied in two ways, foliar and soil, as two independent experiments. The contents of enzymatic (superoxide dismutase, glutathione peroxidase, catalase, ascorbate peroxidase, and phenylalanine ammonia lyase) and non-enzymatic (phenols, flavonoids, and glutathione) antioxidant compounds, the mineral content, flower quality, and shelf life were analyzed. The results showed that the application of SiO2 NPs through the foliar method induced a greater flowers’ shelf life (up to 21.62% more than the control); greater contents of Mg, P, and S (up to 25.6%, 69.1%, and 113.9%, respectively, compared to the control); more photosynthetic pigment (up to 65.17% of total chlorophyll); more glutathione peroxidase activity (up to 69.9%); more phenols (up to 25.93%); and greater antioxidant capacity as evaluated by the DPPH method (up to 5.18%). The use of SiO2 NPs in the production of Lilium is a good alternative method to increase flower quality and shelf life.

Comparative Analysis of the Quality of Domestically Distributed Cut Phalaenopsis Flowers Based on the Season and Place of Origin

This study compared and analyzed the qualities of cut Phalaenopsis “V3” flowers based on the place of origin and season. An investigation of the senescence type showed that flowers originating from Korea had a higher rate of aging than those from China across all three seasons. Consequently, the vase life was also 3–5 days longer for Chinese flowers than those for Korean flowers, regardless of the season. Furthermore, the vase life was the longest in autumn, followed by spring and summer, with statistically significant differences. With respect to flower diameter, Chinese cut phalaenopsis flowers were relatively larger than the Korean ones on day 1 of the experiment. As the senescence process of wilting was initiated earlier in Korean flowers with a shorter vase life, they showed higher reductions in flower diameters as well. The fresh weight, water uptake, and water balance were lower for Korean flowers than those for Chinese flowers starting on day 5 of the experiment across all three seasons. Korean cut phalaenopsis flowers experienced difficulties in maintaining water levels following their water uptake on day 1, which may have affected their vase life. Ethylene production showed a sharp increase on day 7 in Chinese cut flowers and day 5 in Korean cut flowers, with high amounts typically observed in spring, which coincided with the results of water loss. Hunter values L, a, and b and changes petal color ⊿E significantly differed not by place of origin but by season. Additionally, the sugar content of the solution inside the water tubes used when selling cut phalaenopsis flowers was investigated. Chinese flowers are subjected to pretreatment and posttreatment inside the water tube before being exported, while Korean flowers are treated with tap water. The Chinese flowers contained approximately seven times more sugar content compared to Korean flowers. This suggests that the treatment solution components, including sugar and other ingredients, of the Chinese cut flowers had a positive effect on water uptake and lowered the sensitivity to ethylene, which seemed to have an effect on the long vase life and quality. If Korean cut flowers are also distributed using a treatment agent, it is expected that the vase life will be improved and the satisfaction of consumers will be increased. However, since there are several possibilities that can affect post-harvest quality, it seems that additional experiments are needed. Moreover, as flower quality decreases in summer compared to those in spring or autumn, it will be necessary to reduce the differences in quality between seasons.

Resistance varieties and pattern of disease progress of rust (Pucciana horiana p. henn) in Chrysanthemum

Rust is a major disease in chrysanthemum, which causes degradation of flower quality and results in up to 100% yield loss. Out of all the available strategies, breeding for host-plant resistance and knowledge of the pattern of disease progression in each variety is an effective strategy to control rust disease. The disease progress figured out the level of disease severity from time to time. It would be as guidance to control the disease, especially pesticide application. Six national superior and one introduced varieties were tested for their rust resistance. The varieties were studied to know the pattern of disease progression in each variety from vegetative to generative phase. The study was conducted from August 2014 to January 2015 in the plastic house of chrysanthemum plantation at Garung sub-District, Wonosobo regency, one of the centers chrysanthemum production in Central Java. The disease intensity was measured at 30, 60, and 90 days after planting. The results relayed that based on the rate of disease progress and the average of disease intensity, it could be identified that the superior national varieties of chrysanthemum, Kusumaswasti, Marimar, and Yulimar were more resistant to rust than the four other varieties tested. The rate of disease progress and the level of disease intensity of rust by the plant age determined the resistance of the chrysanthemum varieties to rust. Moreover, the result showed that each variety had a different rate and pattern of disease progression and could be used to control rust effectively.

Four-Dimension Deep Learning Method for Flower Quality Grading with Depth Information

Grading the quality of fresh cut flowers is an important practice in the flower industry. Based on the flower maturing status, a classification method based on deep learning and depth information was proposed for the grading of flower quality. Firstly, the RGB image and the depth image of a flower bud were collected and transformed into fused RGBD information. Then, the RGBD information of a flower was set as inputs of a convolutional neural network to determine the flower bud maturing status. Four convolutional neural network models (VGG16, ResNet18, MobileNetV2, and InceptionV3) were adjusted for a four-dimensional (4D) RGBD input to classify flowers, and their classification performances were compared with and without depth information. The experimental results show that the classification accuracy was improved with depth information, and the improved InceptionV3 network with RGBD achieved the highest classification accuracy (up to 98%), which means that the depth information can effectively reflect the characteristics of the flower bud and is helpful for the classification of the maturing status. These results have a certain significance for the intelligent classification and sorting of fresh flowers.