Short-day Treatment Research Articles

Longer Duration of Short-day Treatment Is Required to Advance Flowering and Fruiting of Decaploid Strawberry ‘Tokun’

Strawberry ‘Tokun’ (2n = 10x =70) is a unique cultivar with special flavors, but its late maturity hampers its extension. To advance flowering and fruiting of this decaploid strawberry, the effects of short-day combined with extra nitrogen (N) nutrition treatments on strawberry ‘Tokun’ plants were studied. Runner plantlets of strawberry ‘Tokun’ were harvested and rooted in tray plugs in June 2016, 2017, and 2018, and established plants were conditioned with short-day (SD; 10 hours) and extra N nutrition. The conditioned plants were transplanted into a tabletop substrate culture system in a plastic greenhouse on 27 Aug., 3 Sept., and 10 Sept. during the 3 years, respectively, and the plants received full-element nutrient solution through the drip tube during the whole experimental period. The number of runners and lateral buds, flowering and fruiting periods, and fruit yield were investigated. Longer duration (6–7 weeks) of the SD treatment (10 hours) could significantly reduce the number of runners and increase the number of lateral buds of strawberry ‘Tokun’, advance flowering and fruiting, and achieve a fruit yield of ≈200 g/plant from November to December. The positive effect of extra N nutrition on flowering and fruiting of strawberry ‘Tokun’ was not found. This study is of great practical importance and guiding significance for cultivation and extension of the decaploid strawberry ‘Tokun’.

Transcriptome analysis of the molecular mechanism of Chrysanthemum flower color change under short-day photoperiods

Chrysanthemum [Dendranthema morifolium Tzvel.] is an ornamental plant grown under long-term artificial cultivation conditions. In production, early Chrysanthemum blossoms are often promoted by artificial short-day treatment. However, we found that the flower colour of Chrysanthemum blossoms induced by artificial short-day treatment was lighter than those induced by the natural photoperiod. To explore the intrinsic mechanism of colour fading in flowers, we performed full-length transcriptome sequencing of Chrysanthemum morifolium cv. ‘Jinbeidahong’ using single-molecule real-time sequencing and RNA-sequencing under natural daylight (ND) and short daylight (SD) conditions. The clustered transcriptome sequences were assigned to various databases, such as NCBI, Swiss-Prot, Gene Ontology and so on. The comparative results of digital gene expression analysis revealed that there were differentially expressed transcripts (DETs) in the four stages under ND and SD conditions. In addition, the expression patterns of anthocyanin biosynthesis structural genes were verified by quantitative real-time PCR. The major regulators of the light signalling ELONGATED HYPOCOTYL5 genes were markedly upregulated under ND conditions. The patterns of anthocyanin accumulation were consistent with the expression patterns of CHI1 and 3GT1. The results showed that the anthocyanin synthesis is tightly regulated by the photoperiod, which will be useful for molecular breeding of Chrysanthemum.

Extreme short-day induction requirements for flowering in the late-flowering strawberry cultivar ‘Malwina’

ABSTRACT We studied short-day induction of the strawberry (Fragaria x ananassa Duch.) cultivar ‘Malwina’ under both phytotron and field conditions. Flowering was assessed by crown dissection of treated plants and subsequent flowering performance. Serial dissections revealed no visible changes in crown apices during the first 4 weeks of short day (SD) at 18°C in the phytotron, while after 6 weeks, all plants had formed rudimentary flower primordia with visible sepals. At 9°C, the same stages were reached after 8 and 10 weeks of SD, respectively. When subsequently forced in long day (LD) at 20°C, no substantial flowering took place after less than 6-week SD treatment at 18°C, while full flowering required 10 weeks of SD induction. At 9°C, full flowering was not obtained even after 10 weeks of SD treatment. Under field conditions, the ‘Malwina’ plants did not reach floral development stage 2 before 22 October, approximately a month after ‘Frida’ and ‘Sonata’ which reached this stage on 21 September, and 3 weeks after ‘Florence’. SD exposure resulted in repeated crown branching in ‘Malwina’ and we suggest that early spontaneous abortion of the emerging floral primordium takes place under unsaturated SD induction conditions, thus causing crown branching and hence, delayed floral initiation and development.

Morphology and phenology in Picea abies seedlings in response to split short day treatments

Short-day (SD) treatment is used by forest nurseries to induce growth cessation in Picea abies seedlings. SD treatment may however increase the risk of reflushing in autumn and earlier bud break the following spring. We tested how different starting dates and durations of SD treatment influenced on morphological and phenological traits. Regardless of timing and duration of the SD treatment, height growth was reduced compared to the untreated controls. Seedlings given split SD (7+7 days interrupted with two weeks in long days) had less height growth than all other treatments. Root collar diameter growth was significantly less in control seedlings than in seedlings exposed to early (7 or 14 days) or split (7+7 days) SD treatment. There were also differences in the frequency of reflushing and bud break timing among the SD treated seedlings, dependent on duration and starting date. If the SD treatment started early, a continuous 14-day SD treatment was not sufficient to avoid high frequencies of reflushing. However, by splitting the SD treatment into two periods of 7+7 days these negative effects were largely avoided, although spring bud break occurred earlier than in the controls.

Effect of short-day treatment on expression of CO gene in Chrysanthemum indicum

This experiment studied the expression pattern of key gene CO in the photoperiod of Chrysanthemum indicum. The CDS sequence of the Ch. indicum CO gene was cloned by RT-PCR. The open reading frame was 1 380 bp in length and encoded 459 amino acids. The bioinformatics analysis results showed that the Ch. indicum CO had higher homology with Ch. lavandulifolium and Artemisia annua,and the CO was more conservative in the same family. The molecular weight of the predicted protein encode by CO is 52. 04 k Da,the p I is 4. 81,the α-helix structure accounted for 17. 65%,the random coil accounted for 76. 69%,the extension chain accounted for 5. 66%,there are no β-fold and signal peptide. The experimental results showed that short-day treatment could increase the expression level of CO gene in Ch. indicum and induce its flowering. The results of qRT-PCR showed that the relative expression of CO gene in different tissues and different treatment periods of Ch. indicum was significantly different. In this paper,we studied the effect of short-day treatment on the expression of key genes in the flowering cycle of Ch. indicum,providing a basis for photoperiod regulation and harvesting period of Ch.indicum.

Short-day treatment affects growth, physiological parameters and needle proteome of Chinese pine (Pinus tabuliformis Carr.) seedlings

Previous studies have proven that short-day treatment is an effective means to regulate shoot growth and abiotic stress resistance in conifers. However, the effects on Chinese pine (Pinus tabuliformis) seedlings are less well known. In this study, short-day treatments were applied to container-grown Chinese pine seedlings by artificially reducing day length to 8 or 10 h for 3 weeks. Growth and physiological responses of the seedlings were evaluated. In addition, proteome analysis using two-dimensional electrophoresis in combination with MALDI-TOF/TOF MS analysis was performed on needles of the seedlings. Short-day treatments significantly affected seedling bud set, height, root collar diameter and number of first-order lateral roots (> 1 mm diameter at junction with taproot). Short-day treatments significantly enhanced the content of total chlorophyll, starch, abscisic acid, and lignin, and increased activity of phenylalanine ammonialyase, polyphenol oxidase, and peroxidase, but did not differ in the content of soluble sugar. We positively identified eight differentially expressed proteins induced by short-day treatments: oxygen-evolving enhancer protein 1, transcription factor VOZ1, ferredoxin-NADP reductase, leaf isozyme 1, protein MET1, glyceraldehyde-3-phosphate dehydrogenase, phosphoglycerate kinase 1, elongation factor Tu, and ribulose bisphosphate carboxylase/oxygenase activase. These proteins are mainly involved in photosynthesis, carbohydrate metabolism, as well as abiotic and biotic stress resistance. Our results suggest that short-day treatment is a way to produce high-quality Chinese pine seedlings in the nursery.

Use of short-day treatment in the production of Norway spruce mini-plug seedlings under plant factory conditions

ABSTRACTMini-plug transplant seedlings of Norway spruce have been cultivated in closed growth systems, so-called plant factories, for few years. The aim of the experiment was to define a short-day treatment (SD) that harden seedlings to sustain 3 months of cold storage, but does not have adverse effects on growth, morphology, and vitality. The seedlings were subjected to one of the following treatments: (1) 12 h photoperiod + 3 weeks duration; (2) 8 h photoperiod + 3 wk duration; (3) 12 h photoperiod + 5 wk duration; and (4) 8 h photoperiod + 5 wk SD. All the SD treatments yielded healthy seedlings that grew well after the cold storage. The frost hardiness of the seedlings improved when the photoperiod was reduced from 12 to 8 h, and when the SD duration was increased from 3 weeks to 5 weeks, but reducing the photoperiod from 12 h to 8 h caused growth reductions. The root and shoot regrowth after cold storage was highest in seedlings that had received 12 h photoperiod and 5 wk duration. However, 12 h photoperiod and 3 wk duration may be an adequate practice for nurseries that treat multiple crops in their SD facilities.

Short-day photoperiods affect expression of genes related to dormancy and freezing tolerance in Norway spruce seedlings

Key MessageGene expression analysis showed that prolonged short day (SD) treatment deepened dormancy and stimulated development of freezing tolerance ofPicea abiesseedlings. Prolonged SD treatment also caused later appearance of visible buds in autumn, reduced risks for reflushing, and promoted earlier spring bud break. ContextShort day (SD) treatment of seedlings is a common practice in boreal forest tree nurseries to regulate shoot growth and prepare the seedlings for autumn planting or frozen storage. AimsThe aim of this study was to examine responses of Norway spruce (Picea abies (L.) Karst.) to a range of SD treatments of different length and evaluate gene expression related to dormancy induction and development of freezing tolerance. MethodsThe seedlings were SD treated for 11 h a day during 7, 14, 21, or 28 days. Molecular tests were performed, and the expression profiles of dormancy and freezing tolerance-related genes were analyzed as well as determination of shoot growth, bud set, bud size, reflushing, dry matter content, and timing of spring bud break. ResultsThe 7-day SD treatment was as effective as longer SD treatments in terminating apical shoot growth. However, short (7 days) SD treatment resulted in later activation of dormancy-related genes and of genes related to freezing tolerance compared to the longer treatments which had an impact on seedling phenology. ConclusionGene expression analysis indicated an effective stimulus of dormancy-related genes when the SD treatment is prolonged for at least 1–2 weeks after shoot elongation has terminated and that seedlings thereafter are exposed to ambient outdoor climate conditions.

Context-dependent regulation of pectoralis myostatin and lipid transporters by temperature and photoperiod in dark-eyed juncos

A prominent example of seasonal phenotypic flexibility is the winter increase in thermogenic capacity (=summit metabolism, ) in small birds, which is often accompanied by increases in pectoralis muscle mass and lipid catabolic capacity. Temperature or photoperiod may be drivers of the winter phenotype, but their relative impacts on muscle remodeling or lipid transport pathways are little known. We examined photoperiod and temperature effects on pectoralis muscle expression of myostatin, a muscle growth inhibitor, and its tolloid-like protein activators (TLL-1 and TLL-2), and sarcolemmal and intracellular lipid transporters in dark-eyed juncos Junco hyemalis. We acclimated winter juncos to four temperature (3 °C or 24 °C) and photoperiod [short-day (SD) = 8L:16D; long-day (LD) = 16L:8D] treatments. We found that myostatin, TLL-1, TLL-2, and lipid transporter mRNA expression and myostatin protein expression did not differ among treatments, but treatments interacted to influence lipid transporter protein expression. Fatty acid translocase (FAT/CD36) levels were higher for cold SD than for other treatments. Membrane-bound fatty acid binding protein (FABPpm) levels, however, were higher for the cold LD treatment than for cold SD and warm LD treatments. Cytosolic fatty acid binding protein (FABPc) levels were higher on LD than on SD at 3 °C, but higher on SD than on LD at 24 °C. Cold temperature groups showed upregulation of these lipid transporters, which could contribute to elevated Msum compared to warm groups on the same photoperiod. However, interactions of temperature or photoperiod effects on muscle remodeling and lipid transport pathways suggest that these effects are context-dependent.

Combined effects of short-day treatment and fall fertilization on growth, nutrient status, and spring bud break of Pinus tabulaeformis seedlings

Abstract: Although effects of short-day treatment and fall fertilization on seedling development have been studied independently, their combined influences are not well elucidated. We explored growth, nutrient concentration, and spring bud break of Chinese pine (Pinus tabulaeformis Carr.) seedlings exposed to two photoperiod treatments (short-day consisting of 3 weeks of 18-hr nights in late summer and ambient day length) and three rates of fall N fertilization (0, 12 and 24 mg N per seedling). Seedlings were assessed before fall fertilization and at the end of the growing season. Bud break timing was evaluated the following spring. Increased foliar P concentration concurrent with reduced root P and K concentration occurred in short-day treated seedlings at the conclusion of photoperiod treatment. By the end of the growing season, short-day treatment resulted in greater N and P concentration in the stems, and P concentration in the foliage. It also induced smaller foliage and stem dry mass in both stages. Fall fertilization consistently enhanced tissue N concentration, but interaction effects with short-day treatment were generally non-significant. Short-day treatment curtailed shoot growth, induced terminal bud set, and hastened spring bud break (by only one day) for this mid-latitude seed source (41° N). Thus, short-day treatment or fall fertilization each promoted an increased nutrient concentration, while having only a minor effect on spring bud break.

Short day length-induced decrease of cesium uptake without altering potassium uptake manner in poplar.

Short day length-induced alteration of potassium (K) localization in perennial trees is believed to be a mechanism for surviving and adapting to severe winters. To investigate the relationship between cesium (Cs) and K localizations, a model tree poplar, hybrid aspen T89, was employed. Under short day length conditions, the amount of 137Cs absorbed through the root and translocated to the root was drastically reduced, but 42K was not. Potassium uptake from the rhizosphere is mediated mainly by KUP/HAK/KT and CNGC transporters. In poplar, however, these genes were constantly expressed under short-day conditions except for a slight increase in the expression a KUP/HAK/KT gene six weeks after the onset of the short-day treatment. These results indicated that the suppression of 137Cs uptake was triggered by short day length but not regulated by competitive Cs+ and K+ transport. We hypothesize that there are separately regulated Cs+ and K+ transport systems in poplar.

Technological progress in Japanese horticultural production and its academic aspects

Technological progress is important for advancing crop productivity and quality and efficient production systems in horticulture. In particular, the development of technology has been required for labor saving, good quality (e.g., sweetness) for consumers, and increased functional components for preventing adult disease. Here, recent technological advances in cultivation and breeding, mainly of fruits, in Japan are described with their scientific background. Advanced horticultural technologies in Japan include the joint tree training system, which is labor saving and promotes early and high yield, and the new chestnut (Castanea crenata) cultivar 'Porotan' with the easy-peeling trait. β-Cryptoxanthin has been found to be a useful functional component and rich in Satsuma mandarin (Citrus unshiu). The constant temperature short duration (CTSD) method has been developed to remove the stringency of Japanese persimmon (Diospyros kaki). As technological progress in vegetable production, night chilling and short-day treatment is described with the elevated bed system in strawberry (Fragaria × ananassa) cultivation. In tomato (Solanum lycopersicum), progress in breeding and cultivation is described along with the bioresource project in the postgenome era. The recent development of plant factories draws attention as a future-oriented technology in horticulture. There is still room for development in horticultural production in the Asia-Pacific area. For example, fruit consumption per person in Asia is much lower than that in Europe and North America and, in particular, East Asian countries rank low in fruit consumption per person. Exchanges of technologies and academic knowledge such as those presented in the Asia-Pacific area will have a strong impact on horticultural science and production in the next decade.

Responses of chilling resistance to photoperiodic dormancy induction in peach leaf.

Taking 6-year-old "Chunjie" peach as test material, and the peach in natural condition as the control, this paper investigated induced effects of long-day and short-day photoperiod on dormancy and responses of chilling resistance to photoperiodic induction during dormancy induction process. The results showed that the trees of long-day and short-day treatments could both enter dormancy induction under the gradually decreasing temperature. The long-day treatment was 1 week later than the control, while the short-day treatment was 1 week earlier. The total water content and free water content both decreased, and the bound water content and the ratio of bound water/total water increased with the development of dormancy. SOD and CAT activities changed as unimodal curve during dormancy induction, and the peak values appeared at the late stage of dormancy induction, POD activity decreased rapidly after the start of dormancy induction, and rebounded to form a small peak at the late stage of dormancy induction. The soluble protein content declined, proline and malonaldehyde (MDA) increased continuously, and the injury rate increased. Long-day could increase SOD and CAT activities and proline content, alleviate the decline of POD activity and soluble protein content, and reduce the growth rate of MDA and injury rate, which indicated leaf damage was lighter in long-day treatment than in the control. However, they changed differently under short-day treatment, especially the leaf injury rate was higher than the control, exhibiting a lower chilling resistance. Prolonging illumination was suggested to improve leaf chilling resistance in practical production if environmental temperature permitted.

DNA demethylation during Chrysanthemum floral transition following short-day treatment

Background: The analytic techniques of methylation-sensitive amplification polymorphism and high-performance liquid chromatography were employed to detect variation DNA methylation of mature leaves of Chrysanthemum during the floral transition induced by short-day (SD) treatment. Results: The time to capitulum bud appearance and early blooming from the date of planting were significantly shorter than those of the control for both an early and late-flowering cultivar. Capitulum development of the early- flowering cultivar was significantly accelerated compared with that of the control, which was different with the late-flowering cultivar. DNA methylation percentage of leaves changed dynamically during flower development. For the early-flowering cultivar, DNA methylation was 42.2%-51.3% before capitulum bud appearance and 30.5%-44.5% after capitulum bud appearance. The respective DNA methylation percentages for the late-flowering cultivar were 43.5%-56% and 37.2%-44.9%. Conclusions: Percentage DNA methylation of leaves of Chrysanthemum decreased significantly during floral development. The decline in DNA methylation was elevated in the early-flowering cultivar compared with that of the late- flowering cultivar.

Determination of Photoperiod-Sensitive Phase in Chickpea (Cicer arietinum L.).

Photoperiod is one of the major environmental factors determining time to flower initiation and first flower appearance in plants. In chickpea, photoperiod sensitivity, expressed as delayed to flower under short days (SD) as compared to long days (LD), may change with the growth stage of the crop. Photoperiod-sensitive and -insensitive phases were identified by experiments in which individual plants were reciprocally transferred in a time series from LD to SD and vice versa in growth chambers. Eight chickpea accessions with differing degrees of photoperiod sensitivity were grown in two separate chambers, one of which was adjusted to LD (16 h light/8 h dark) and the other adjusted to SD (10 h light/14 h dark), with temperatures of 22/16°C (12 h light/12 h dark) in both chambers. The accessions included day-neutral (ICCV 96029 and FLIP 98-142C), intermediate (ICC 15294, ICC 8621, ILC 1687, and ICC 8855), and photoperiod-sensitive (CDC Corinne and CDC Frontier) responses. Control plants were grown continuously under the respective photoperiods. Reciprocal transfers of plants between the SD and LD photoperiod treatments were made at seven time points after sowing, customized for each accession based on previous data. Photoperiod sensitivity was detected in intermediate and photoperiod-sensitive accessions. For the day-neutral accession, ICCV 96029, there was no significant difference in the number of days to flowering of the plants grown under SD and LD as well as subsequent transfers. In photoperiod-sensitive accessions, three different phenological phases were identified: a photoperiod-insensitive pre-inductive phase, a photoperiod-sensitive inductive phase, and a photoperiod-insensitive post-inductive phase. The photoperiod-sensitive phase extends after flower initiation to full flower development. Results from this research will help to develop cultivars with shorter pre-inductive photoperiod-insensitive and photoperiod-sensitive phases to fit to regions with short growing seasons.

Molecular and Functional Characterization of FLOWERING LOCUS T Homologs in Allium cepa.

Onion bulbing is an important agricultural trait affecting economic value and is regulated by flowering-related genes. FLOWERING LOCUS T (FT)-like gene function is crucial for the initiation of flowering in various plant species and also in asexual reproduction in tuber plants. By employing various computational analysis using RNA-Seq data, we identified eight FT-like genes (AcFT) encoding PEBP (phosphatidylethanolamine-binding protein) domains in Allium cepa. Sequence and phylogenetic analyses of FT-like proteins revealed six proteins that were identical to previously reported AcFT1-6 proteins, as well as one (AcFT7) with a highly conserved region shared with AcFT6 and another (comp106231) with low similarity to MFT protein, but containing a PEBP domain. Homology modelling of AcFT7 proteins showed similar structures and conservation of amino acids crucial for function in AtFT (Arabidopsis) and Hd3a (rice), with variation in the C-terminal region. Further, we analyzed AcFT expression patterns in different transitional stages, as well as under SD (short-day), LD (long-day), and drought treatment in two contrasting genotypic lines EM (early maturation, 36101) and LM (late maturation, 36122). The FT transcript levels were greatly affected by various environmental factors such as photoperiod, temperature and drought. Our results suggest that AcFT7 is a member of the FT-like genes in Allium cepa and may be involved in regulation of onion bulbing, similar to other FT genes. In addition, AcFT4 and AcFT7 could be involved in establishing the difference in timing of bulb maturity between the two contrasting onion lines.

Three FLOWERING LOCUS T-like genes function as potential florigens and mediate photoperiod response in sorghum.

Sorghum is a typical short-day (SD) plant and its use in grain or biomass production in temperate regions depends on its flowering time control, but the underlying molecular mechanism of floral transition in sorghum is poorly understood. Here we characterized sorghum FLOWERING LOCUS T (SbFT) genes to establish a molecular road map for mechanistic understanding. Out of 19 PEBP genes, SbFT1, SbFT8 and SbFT10 were identified as potential candidates for encoding florigens using multiple approaches. Phylogenetic analysis revealed that SbFT1 clusters with the rice Hd3a subclade, while SbFT8 and SbFT10 cluster with the maize ZCN8 subclade. These three genes are expressed in the leaf at the floral transition initiation stage, expressed early in grain sorghum genotypes but late in sweet and forage sorghum genotypes, induced by SD treatment in photoperiod-sensitive genotypes, cooperatively repressed by the classical sorghum maturity loci, interact with sorghum 14-3-3 proteins and activate flowering in transgenic Arabidopsis plants, suggesting florigenic potential in sorghum. SD induction of these three genes in sensitive genotypes is fully reversed by 1 wk of long-day treatment, and yet, some aspects of the SD treatment may still make a small contribution to flowering in long days, indicating a complex photoperiod response mediated by SbFT genes.

Effects of Short-Day and Gibberellic Acid Treatments on Summer Vegetative Propagation of Napier Grass (Pennisetum purpureumSchumach)

The effects of short-day (SD) and gibberellic acid (GA3) treatments on promoting vegetative propagation during the summer were examined in Napier grass (Pennisetum purpureumSchumach). A dwarf variety of late heading type (DL) Napier grass was exposed to three SD treatments (5, 10, and 20 short days plus a spray of 400 ppm GA3solution following each SD treatment, GASD) or no treatment (control). Additionally, then, a dwarf variety of early heading (DE) and the normal variety of Merkeron (ME) were exposed to 10 days of GA-SD treatment together with nontreated controls. For DL and DE, GA-SD treatments showed the following effects: 10-day GA-SD treatment increased significantly (P<0.05) the length of lateral tiller buds, maintained a high rooting percentage, and increased the diameter of the tiller buds. This resulted in a taller plant, one with enhanced tiller numbers, and thus a greater number of established nursery plants for the two dwarf varieties. In contrast, there was only a limited positive effect of the GA-SD treatments on the normal variety, ME. Thus, 10 days of GA-SD treatment was judged to be the most effective treatment for promoting lateral tiller bud elongation and early maturation in tiller buds for the two dwarf varieties of Napier grass.

<i>Hosta yingeri</i> S.B.Jones における発芽に及ぼす温度の影響と生育に及ぼす日長の影響

The aims of this study were to examine the effects of different temperatures on seed germination and initial long-day (LD) or short-day (SD) duration on growth, floral initiation, and development of Hosta yingeri S.B.Jones. The germination percentage of H. yingeri seeds was > 90% at 5°C and between 15°C–30°C. The lowest time to the first germination (TFG) and the mean germination time (MGT) were observed at around 30°C. The optimum temperature for germination can be around 30°C considering the final germination percentage, TFG, and MGT together. Plant height, number of leaves, and leaf length increased as the initial SD duration decreased. The percentages of plant bearing buds were 50%, 50%, 20%, 10%, and 0% when the initial SD treatments were 0, 3, 6, 9, and 12 weeks with 29, 26, 23, 20, and 17 weeks of LDs, respectively. No plants flowered when they were exposed to the initial LD conditions. Flower spike length, number of visible buds, and number of open flowers increased as the duration of the initial SD decreased. Four-week-old H. yingeri required ≥ 26 weeks of LD duration to achieve > 50% flowering.

웹 카메라를 이용한 시설 내 국화생산 광 환경 원격 모니터링

Increase of national family income improved demand of high-quality and year-round horticultural products including chrysanthemum. To meet these demand, farmers have introduced protected facilities, such as greenhouses, of which environmental conditions could be monitored and controlled. Environment management up to three weeks after transplanting is critical for chrysanthemum quality. Artificial lighting and light-blocking screen are especially important for long-day (day period > 13 hours) and short-day (night period > 13 hours) treatments. In this study, a web-camera was installed, and the image was obtained and transmitted to mobile phones to monitor the status of 3-wavelength(RGB) lighting environments. RGB pixel values were used to determine malfunctioning of the lighting lamps, and leaking out and incoming illumination status during short-day and long-day treatment periods. Normal lighting lamps provided RGB pixel values of 240～255. During long-day treatment period, G pixel values were useful to detect abnormal lighting conditions (e.g., leaking). During short-day treatment period, R pixel values were useful to determine incoming light (e.g., sun-light). Results of this study would provide useful information for remote monitoring of light conditions for protected chrysanthemum production under artificial lights.