Flower Opening Research Articles

Effect of biofertilizer on growth and yield attributes of ridge gourd (Luffa acutangula L.) under zone -7 of (Davangere, district) Karnataka

An experiment on Ridge gourd (Luffa acutangula L.) Effect of Biofertilizer on growth and yield attributes of Ridge gourd (Luffa acutangula L.) under zone -7 of Karnataka. The experiment was carried out at diploma (Agri) College Agricultural and Horticultural Research Station, Kathalagere, Davangere. In kharif season during the year 2022 with three replicated randomized block designs. with seven treatments in 6.5 x 5.5 m plot size twelve plant population was maintained in each plot with normal spacing given 1.5x1.5 m row and plant to plant respectively. The results of the experiment revealed Treatment T-5 (75% NPK + FYM +VC 1250 Kg/ha+ biofertilizer (Pseudomonous flourscence @ 2.50 kg/ha and Trichoderma viridae @ 750 g/ha) was shows better results recorded more number of primary branches/shoots(5.45 no) vine length (482.75 Cm) Leaves /plant (66.83 Nos) earliest opening of first female flower shows in in DAS (40.58) highest fruit length / diameter also (45.08 /8.26 Cm and fruit Yield recorded in (1.45kg), 15.06 kg) & (4635.89 kg) plant,/plot and hector respectively.

EFFECT OF NITROGEN RATES ON GROWTH, FRUIT AND SEED YIELD OF OKRA (Abelmoschus esculentus L. Moench)

A Field trial was conducted at the Teaching and Research Farm of the Federal University of Technology, Minna (Southern Guinea Savanna ecological zone of Nigeria) during the 2019 and 2020 cropping seasons. The experiment was laid out in a Randomized Complete Block Design and replicated three times. The treatments consisted of two okra varieties (NHAe47-4 and LD 88) and five rates of nitrogen fertilizer (0, 30, 60, 90 and 120 kg N ha-1). Each plot measures 2×5.25 m (10.5m2) comprising of eight ridges. Parameters measured included days to first flower bud initiation and opening, days to 50% flowering, plant height, number of leaves, abortion incidence, number of productive branches, number of fresh fruits, number of seeds, weight of seed and 100 seed weight were determined among others. Data collected were subjected to analysis of variance (ANOVA) using SAS Statistical package 9.2. At 5% level of probability means were separated using Student- Newman Keuls (SNK) Test. Application of 90kg N/ha to okra is therefore suggested for good growth, improved fruit and seed yield in the studied zone. NHAe47-4 fruits contained more number of seeds than LD88 variety.

Response of fertilizer and planting time on yield and economics of Zucchini (Cucurbita pepo) in Assam condition

In the agricultural sector, the vitally important factors to achieve higher production in a crop are fertilizer management and planting time. To maintain healthy plant growth and to boost crop production and productivity, fertilizer application, and planting dates have a pivotal role in the present scenario of climate change. However, the effect of fertilizer and planting dates on zucchini in agro-climatic conditions of Assam has not been properly studied. So, during the year 2019-20, it was assessed in the Experimental Farm, Department of Horticulture, Assam Agricultural University, Jorhat. Four fertilizer treatments 45: 48: 48 kg NPK/ha, 60: 64: 64 kg NPK/ha, 75: 80: 80 kg NPK/ha and keeping one treatment as control with three planting dates 1st December, 15th December, 1st January was imposed in twelve treatment combinations. The zucchini seedlings were planted at a 60 cm x 60 cm distance in a plot size of 3.24 m2 in a split-plot design. During the growing period, the diameter of fruit, length of fruit, weight of fruit, number of days to opening of flower to harvest, number of days to first harvest, number of days to last harvest, number of harvests, number of fruits per plant and fruit yield per plant/ plot/ hectare were recorded. From this trial, it is concluded that early planting and maximum fertilizer dose were better in terms of the above physical and yield attributes. Therefore, based on the findings of the experiment, it is hereby inferred that planting of zucchini on the 15th of December with a fertilizer dose of 75: 80: 80 kg NPK/ha showed the best result with maximum yield (82.59 t) per hectare area with (3.46) B:C ratio in Assam growth condition.

Postharvest treatments to optimize long-term storage of cut peony flowers

Cut peonies have limited time during which they can be harvested and commercialized. Interest in extending this period through long-term storage, both in dry and wet conditions, to obtain more profits is constantly growing. Sixty cut peony stems (cv. Alertie) were pulse-treated 24 h after harvest with 10 μM thidiazuron, 500 μL L-1 1-methylcyclopropene, 10 mM glycerol, and a combination of them (All) in a refrigerated cell at 4 °C, where the flowers were stored with wet preservation for 15 and 30 days. After these periods, flowers were maintained at 20 °C, and their quality was assessed through in vivo and destructive analyses at 0, 4, 12, and 14 days. Thirty days of storage strongly inhibited flower opening, in contrast to the shorter preservation period. After 15 days of storage and during preservation at room temperature, flowers treated with glycerol showed less water loss and senescence symptoms. Nitrate and phenol concentrations increased in all treatments after storage. In conclusion, wet storage at 4 °C for 15 days was more suitable for the cultivar tested in the present study and it also allowed the identification of treatments that involved the use of glycerol as promising for long-term preservation of peonies and their vase-life.

Desenvolvimento e funcionamento de sacos embrionários em quatro cultivares triploides de banana

Abstract The objective of this work was to investigate the causes of sterility in a new set of triploid banana (Musa spp.) cultivars and to assess the chances of obtaining some progenies by manual cross-pollination. The developmental stages of female gametophyte were histologically recorded in ovules of four distinct triploid banana cultivars. Samples were taken on the day of flower opening and pollination and three days later. Morphologically mature embryo sacs were very rare in the two clones of the 'Cavendish' subgroup and in 'Prata Anã'. In 'Mysore', it occurred at a variable and low frequency. In 'Terrinha', it was extremely common. In the last two cases, the embryo sac maturation process was clearly continuing between the sampling days of flower opening and three days later. No pollen tube was positively identified in pollinated flowers within the integuments of any ovule of the older explants. Different proportions of mature embryo sacs are observed among the studied triploid genotypes of banana. The presence of mature embryo sacs is not an indication of functional capacity. Other causes of infertility in cultivated bananas can be due to some event immediately before or after fertilization, for instance, pollination tube growth failure or seed abortion.

A aplicação de película natural melhora a conservação de flores de corte de cravos

ABSTRACT Carnation (Dianthus caryophyllus) is one of the most important and popular cut flowers for the ornamental industry. However, it has a short decorative life, being water loss one of the main challenges. Water loss leads the petals to wither with a consequent loss of its commercial value. One of the techniques used in postharvest technology is the use of coatings and films, which interfere in gas exchange and water loss, maintaining the quality of cut flowers. The current study investigated the effects of a natural coating based on hydroxypropyl methylcellulose (HPMC) at 5% and beeswax (BW) in cut carnation flower cv. Delphi stored at 20°C and 70% RH. The application of HPMC + 40% BW treatment in flowers resulted in 30% higher fresh weight, 17% higher relative water content (RWC) and 80% higher flower opening compared to untreated flowers. The shelf life of untreated and HPMC + 40% BW carnations was 7 and 12 days, respectively, allowing a shelf-life extension of up to five days.

Pollination biology of Maianthemum s.s. (Asparagaceae) in different parts of its range

Maianthemum F.H. Wigg. is a genus of perennial plants inhabiting temperate and subtropical regions of Eurasia and North America. Maianthemum sensu stricto includes just a few species that have a wide geographic distribution, are morphologically close, and possess open flowers adapted for a wide range of flower visitors. The present study is aimed at investigating the pollination biology of Maianthemum s.s. A comparison of the pollination biology of these species growing in the same area allows us to clarify ecological differences between the species. Investigation of the pollination biology of the same species in different parts of its range allows for the specification of variation in range of pollinators due to the environmental conditions. We studied pollination of M. bifolium in two far-apart locations (Moscow Region and Primorye Territory); also, in parallel, we studied three species M. bifolium, M. dilatatum, and M. intermedium in the same location in Primorye Territory. Proterandry is typical of all Maianthemum ssp. populations studied here. The studied species have a wide range of flower visitors. All of them can contribute to pollination, but the most stable and effective pollinators of Maianthemum s.s. are bees (Anthophila) and hoverflies (Syrphidae). Geographical position of population is the most important factor defining the range of pollinators of Maianthemum bifolium. The range of pollinators is weakly specific to the three species of Maianthemum s.s.

Characters Association and Path Coefficient Analysis among Quantitative Traits of Chrysanthemum (Dendranthema×Grandiflora Tzvelev)

The present experiment was carried out under naturally ventilated polyhouse at the experimental farm of Division of Flower and Medicinal Crops, ICAR-Indian Institute of Horticultural Research, Bengaluru, Karnataka, India for two years during 2019 (August-November) and 2020 (August-December) The experiment was laid out in completely randomized design (CRD) with three replications under naturally ventilated polyhouse. Analysis of variance showed significant differences among genotypes for all the traits. Results revealed that the days to optimum flowering exhibited positive and significant correlation with plant height (0.599), days to bud initiation (0.628), days to first flower opening (0.985) and flowering duration (0.571), whereas, positive significant correlation with flower diameter (0.324). The results of path coefficient analysis using correlation coefficients revealed that days to first flower opening (1.033) exhibited positive and very high direct effect on days to optimum flowering while, number of leavesplant-1 (0.040), days to bud initiation (0.056), flower diameter (0.025) and flower duration (0.022) showed positive and negligible direct effect. Therefore, the selection on the basis of traits viz., plant height, days to bud initiation, days to first flower opening, flower duration and flower diameter will be more effective for improvement of the flowering traits in chrysanthemum breeding.

Effects of Some Plant Growth Regulators on Quality of Potted Sunflower

This study was carried out to evaluate the effects of different plant growth regulators on the ornamental sunflower plant. The seedlings belonging to Helianthus annuus L. cv. Sunsantion F1 were planted in plastic pots (2 L) containing peat:perlite (1:1, v/v) medium at four true leaf stage. Spray treatments of aminoethoxyvinil glycine (AVG; 250 and 500 ppm), promalin (5 and 10 ppm), thidiazuron (TDZ; 5-10 µM), ethephon (100 ppm) were applied to seedlings 20 days after transfering to the pots, and treatments were repeated 10 days after the first application. Flower life (days), flower diameter (cm), stem diameter (cm) and plant height (cm) were determined. According to statistical analysis, AVG at 250 ppm significantly increased the flower life from 9.17 d in control plants to 11.08 d whereas there were no significant effects on flower diameter and plant height. Both concentrations of Promalin and TDZ increased stem diameter significantly. However, TDZ increased the flower life from 9.17 d (control plants) to 10.36 at 10 µM and 10.33 at 5 µM TDZ. Ethephon application prevented flower bud opening and caused the leaves to be yellowing. These results may suggest AVG and TDZ pre-treatments increase the quality and shelf-life of the potted sunflower plant.

Morphological Characterization and Evaluation Of Snake Gourd Genotypes for Fruit Yield, Yield Attributes and Other Characters

The experiment was conducted at the research field of Horticulture Department of Bangabandhu Sheikh Mujibur Raman Agricultural University (BSMRAU) during the period from March to June 2017 to characterize and evaluate the snake gourd genotypes morphologically. In the study, 55 snake gourd genotypes collected from Plant Genetic Resources Centre (PGRC) of Bangladesh Agricultural Research Institute (BARI), Genetics and Plant Breeding Department of BSMRAU, different seed companies and various parts of Bangladesh. The genotypes exhibited 67.3% cylindrical, 21.8% elliptical, 1.8% fusiform, 9.1% ovate shape fruit along with 56.4% green, 18.2% light green, 16.4% dark green and 9.0% white fruit. Seed colour with 38.2% was brown and 83.6% seed shape was elliptical. The fruit length varied from 12 to 54 cm while fruit diameter varied from 3.5 to 5.5 cm. Days to 1st female flower opening ranged between 44 and 62 days and nodes number on female flower initiation was between 12 and 26. Days to 1st fruit harvest varied from 54 to 72 days. The number of fruits/plants ranged from 8.33 to 27, whereas individual fruit weight varied from 90 to 325g. Fruit yield/plant ranged from 1.29 to 7.74 kg. Genotypes were TC01, TC03, TC04, TC05, TC07, TC08 and TC19 identified as early maturity. The genotypes differed significantly in most of the parameters and offer a good scope for selection of parent for crop improvement programme.
 Bangladesh J. Agril. Res. 45(4): 349-370, December 2020

The application of 28-homocatasterone brassinosteroid reduces blossom end rot in ‘BRS Montese’ tomatoes

We assessed the effect of 28-homocatasterone on xylem functionality and its relationship with blossom end rot (BER) occurrence and the quality of 'BRS Montese' tomatoes. Tomato plants were cultivated in a protected environment, with a semi-hydroponic system. During full flowering, open flowers were selected, marked, and pollinated. After two days, the flowers received the application of 28-homocatasterone at a concentration of 10-6 M or deionized water (control). Treatments were reapplied weekly up to 24 days after the first application (DAFA). At 24 DAFA, fruits were harvested and evaluated for fresh mass, texture (skin rupture and pulp penetration forces), skin color, xylem functionality, membrane permeability, apoplastic calcium concentration, and BER incidence. The application of 28-homocatasterone at 10-6 M did not increase the fresh mass nor change the fruits' texture attributes. However, 28-homocatasterone increased or kept xylem functionality, which was assicated with increased apoplastic calcium concentration and reduced BER occurrence in 'BRS Montese' tomatoes. Thus, the application of 10-6 M catasterone could be an alternative for BER control in tomatoes.

Comparative Transcriptome Analysis of CCCH Family in Roles of Flower Opening and Abiotic Stress in Osmanthus fragrans

CCCH is a zinc finger family with a typical CCCH-type motif which performs a variety of roles in plant growth and development and responses to environmental stressors. However, the information about this family has not been reported for Osmanthus fragrans. In this study, a total of 66 CCCH predicted genes were identified from the O. fragrans genome, the majority of which had multiple CCCH motifs. The 66 OfCCCHs were found to be unevenly distributed on 21 chromosomes and were clustered into nine groups based on their phylogenetic analysis. In each group, the gene structure and domain makeup were comparatively conserved. The expression profiles of the OfCCCH genes were examined in various tissues, the flower-opening processes, and under various abiotic stresses using transcriptome sequencing and qRT-PCR (quantitative real-time PCR). The results demonstrated the widespread expression of OfCCCHs in various tissues, the differential expression of 22 OfCCCHs during flower-opening stages, and the identification of 4, 5, and 13 OfCCCHs after ABA, salt, and drought stress treatment, respectively. Furthermore, characterization of the representative OfCCCHs (OfCCCH8, 23, 27, and 36) revealed that they were all localized in the nucleus and that the majority of them had transcriptional activation in the yeast system. Our research offers the first thorough examination of the OfCCCH family and lays the groundwork for future investigations regarding the functions of CCCH genes in O. fragrans.

Stamen curvature and temporal flower closure assure reproductive success in an early-spring-flowering perennial in the cold desert of Middle Asia.

Floral organ movements that ensure autonomous selfing are likely to occur in species that grow in habitats with pollinator scarcity and/or an unpredictable environment. Stamen curvature and temporal flower closure are two important floral behaviors that can influence plant pollination mode and reproductive success. However, both behaviors are rarely reported within a species, and little is known about how these two movements of floral organs ensure reproductive success in an unpredictable early spring environment with few pollinators. The aim of this study was to assess whether stamen curvature and temporal flower closure ensure successful reproduction of Leontice incerta in its cold desert habitat. Flowering phenology, floral traits, stamen curvature patterns and flower visitors were surveyed. The breeding system, capacity and timing for autonomous selfing were estimated by pollination manipulations. The timing of floral opening and closure, and benefits of temporal flower closure were determined. We found that flowering of L. incerta began in late March to early April in two populations in two years, and the yellow flowers had neither nectar nor scent. Floral visitation occurred very rarely, but bees (Colletes sp.) were potential pollinators. Fruit and seed set of open and bagged flowers did not differ significantly from that of self-pollinated or cross-pollinated flowers. However, removal of stamens significantly decreased seed set. Self-pollination occurs when the stamens curve and anthers touch the stigma autonomously, suggesting autonomous selfing assurance of seed production in this self-compatible species. Both fruit and seed set of flowers that were prevented from closing were significantly lower than those of control flowers and closed flowers treated with simulated rain treatment. Therefore, stamen curvature and temporal floral closure can ensure successful sexual reproduction of L. incerta in early spring in the cold desert, where lack of pollinators otherwise may lead to pollination failure.

Jasmonate-deficient mutant lox3a reveals crosstalk between jasmonate and ethylene in the differential regulation of male and female flower opening and early fruit development in Cucurbita pepo.

Jasmonate (JA) has been found to be a relevant hormone in floral development in numerous species, but its function in cucurbit floral development and sex determination is unknown. Crosstalk between JA and ethylene (ET) in the differential regulation of male and female floral development was investigated by using the novel JA-deficient mutant lox3a, and the ET-deficient and -insensitive mutants, aco1a and etr2b, respectively, of Cucurbita pepo. The lox3a mutation suppresses male and female flower opening and induces the development of parthenocarpic fruit. A bulked-segregant analysis coupled with whole genome sequencing and fine mapping approach allowed the identification of lox3a mutation in CpLOX3A, a LIPOXYGENASE gene involved in JA biosynthesis. The reduced JA content and expression of JA-signalling genes in male and female flowers of lox3a, and the rescue of lox3a phenotype by external application of methyl jasmonate (MeJA), demonstrated that JA controls petal elongation and flower opening, as well as fruit abortion in the absence of fertilization. JA also rescued the phenotype of ET mutants aco1a and etr2b, which are both specifically defective in female flower opening and fruit abortion. ET, the sex determining hormone of cucurbits, is induced in female flowers towards anthesis, activating JA production and promoting the aperture of the female flower, and the abortion of the unfertilized ovary. Given the close association between flower closure and parthenocarpic fruit development, we propose that flower opening can act as a switch that triggers fruit set and development in fertilized ovaries, but may alternatively induce the abortion of the unfertilized ovary. Both ET and JA from mature and senescent petals can serve as remote signals that determine the alternative development of the ovary and fruit.

Qualidade de hastes florais de lisianthus (Eustoma grandiflorum Raf.) inoculadas com Bacillus subtilis e Glomus intraradices

Abstract Lisianthus (Eustoma grandiflorum) is an ornamental species used as a potted plant or cut flower, its popularity is due to the diversity of colors, number of flower buds, and shelf life. Nevertheless, during the first phases of development, problems such as foliar chlorosis and root diseases affects most cultivars, causing poor growth, thin stems, and few flowers. The use of plant growth-promoting rhizobacteria (PGPR) and arbuscular mycorrhizal fungi (AMF) improved plant growth as these microbes colonize the plant system root. Therefore, in order to provide better conditions for the stem development, the aim of this work was to evaluate the individual and combined effect of Bacillus subtilis (PGPR) and Glomus intraradices (AMF) on the growth and postharvest quality of the stems of lisianthus cv. Mariachi. Then commercial product Alubión-X (Bacillus subtilis (PGPR) and mycorrhizal fungus (Glomus intraradices) were used. The variables evaluated were stem height and diameter, foliar area, leaves number and in postharvest, buds number, open and diameter of flowers and stem dry weight. The results showed a significant effect of the inoculation of G. intraradices on the size (66.92 cm) of the stem, as well as the combination of B. subtilis + G. intraradices (65.51 cm) compared to the control (36.9 cm). The number of buds and open flowers of the stems treated with G. intraradices were 33.35 and 23.9 respectively significantly higher than the control. G. intraradices alone is the best option for applying to lisianthus, when compared to applying with B. Subtilis.

Transcriptome Analysis Revealing the Interaction of Abscisic Acid and Cell Wall Modifications during the Flower Opening and Closing Process of Nymphaea lotus.

As a tropical flower, Nymphaea lotus is a typical night-blooming waterlily used in water gardening. Its petals are rich in aromatic substances that can be used to extract essential oils and as flower tea. However, the short life of the flower seriously affects the development of its cut flowers. At present, neither the mechanism behind the night-opening waterlily flower's opening and closing nor the difference between day-opening and night-opening waterlily flowers' opening and closing mechanisms are clear. In this study, endogenous hormone contents of closed (CP) and open (OP) petals were measured, and transcriptome analysis of CP and OP petals was carried out to determine the signal transduction pathway and metabolic pathway that affect flower opening and closing. ABA and cell wall modification were selected as the most significant factors regulating flowering. We used qRT-PCR to identify the genes involved in the regulation of flower opening in waterlilies. Finally, by comparing the related pathways with those of the diurnal type, the obvious difference between them was found to be their hormonal regulation pathways. In conclusion, the endogenous ABA hormone may interact with the cell wall modification pathway to induce the flowering of N. lotus. Our data provide a new direction for the discovery of key factors regulating the flower opening and closing of N. lotus and provide basic theoretical guidance for future horticultural applications.

Effects of semi-decomposed weeds as substrate on plant growth, antioxidant capacity, and leaf nutrition of plum trees

Sustainable practices are inevitable requirements for modern agriculture. Incorporating weed waste into an organic substrate is one of such sustainable agricultural practice. We aimed to investigate whether semi-decomposed, aboveground weed biomass can be used as a substrate for plums. “Qingcui” plums were planted in boxes with semi-composted weeds, and garden soil without composted weeds was used as a control. Plant branch characteristics, leaf antioxidant capacity, leaf nutrition, and numbers of opening flowers and bearing fruits were analyzed. The results showed that treatment with semi-composted weed treatment significantly increased the stem diameter, effective branch number, and effective branch angle. The contents of the reduced glutathione, oxidized glutathione, and the levels of total antioxidant capacity and catalase were significantly higher in semi-composted weeds than in the control group. The macroelement content in the semi-composted weed group was higher than that of the control group, but the microelement contents did not show any significant differences. However, the trace elements and heavy metals showed heterogeneous changes. The Σ DOP of macroelements, microelements, and trace elements in the weed-compost treatment were larger than that in the control. The chlorophyll content in the weed-compost group was significantly higher than that in the control during the leaf abscission period. The leaf weight per area was significantly higher than that of the control, but the growth time was longer. The numbers of total opening flowers and fruit were higher in the semi-composted weed group than in the control group. We demonstrated that semi-composted weeds as substrates have beneficial effects on plum branch characteristics, leaf antioxidant capacity, and generative growth. However, it increases the degree of nutritional imbalance and extends growth time.

Effect of grazing disturbance on floral display, pollen limitation and plant pollination efficiency in the desert steppe

BackgroundGrazing disturbance usually affects floral display and pollination efficiency in the desert steppe, which may cause pollen limitation in insect-pollinated plants. Effective pollination is essential for the reproductive success of insect-pollinated plants and insufficient pollen transfer may result in pollen limitation. Caragana microphylla Lam is an arid region shrub with ecological importance. Few studies have been conducted on how grazing disturbance influences pollen limitation and pollination efficiency of C. microphylla. Here, we quantify the effect of different grazing intensities on floral display, pollinator visitation frequency and seed production in the Urat desert steppe.ResultsIn C. microphylla, supplemental hand pollination increased the seed set, and pollen limitation was the predominant limiting factor. As the heavy grazing significantly reduced the seed set in plants that underwent open-pollination, but there was no significant difference in the seed set between plants in the control plots and plants in the moderate grazing plots. Furthermore, there was a higher pollinator visitation frequency in plants in the control plots than in plants in the heavy grazing plots.ConclusionsWe found that pollinator visitation frequency was significantly associated with the number of open flowers. Our findings also demonstrated that seed production is associated with pollinator visitation frequency, as indicated by increased seed production in flowers with higher pollinator visitation frequency. Therefore, this study provides insight into the effect of different grazing intensities on floral display that are important for influencing pollinator visitation frequency and pollination efficiency in desert steppes.

Role of night interruption lighting and NPK application on growth and flowering of Phalaenopsis

• NIL quality and NPK fertilizers differentially affect growth and flowering of Phalaenopsis. • Under the NI-B treatment, days to the first flower opening and leaf area index were increased. • The highest leaf area and dry weight were found in 19-6-20 NPK exposed plant. • NPK fertilizer 12-12-36, led to an increase of P and K contents and a decrease of Ca level in leaves. Phalaenopsis orchid (the moth orchid; Phalaenopsis spp.) is the most sold indoor's potted plant in the world's major floriculture markets. In the present study, the effects of night interruption light (NIL) quality and different NPK fertilizers were evaluated on the vegetative growth and flowering of Phalaenopsis orchid ‘Evolution’ in a factorial experiment based on Randomized Complete Block Design (RCBD) with three replications. In the first factor, six-old month plants from the last days of August to October, when the length of flower buds was about 5 cm, were grown under NIL in the controlled chambers of a greenhouse. NI was provided by white (NI-W), red (NI-R) and blue (NI-B) LEDs at the significantly reduced intensity of 15-23 μmol m −2 s −1 PPF. The NIL qualities employed for 4-h a day throughout the dark period. Control plants received 10 h of light during the day. In the second factor, three water-soluble NPK fertilizers including 19-6-20, 12-12-36 and 20-20-20 were applied separately throughout the entire vegetative and reproductive stage to plants at the concentration of 1 g L −1 . According to the results, NI-W and NI-B reduced the leaf area compared to the control, while NI-R had no effect. Flowering was not affected by the NIL quality, and all plants flowered upon employed treatments. Under the NI-B treatment, days to the first flower opening, as well as leaf area, were increased; meanwhile, chl a, b , total chl, carotenoid, and the number of leaves and florets in an inflorescence were decreased. Among NPK fertilizers, the highest leaf area and dry weight were found in 19-6-20 NPK. Flowering yield was practically unaffected by the kind of the NPK fertilizer used. However, NPK fertilizer 12-12-36, led to an increase of P and K contents and a decrease of Ca content in the leaves of plant during the reproductive stage. These results suggest that both NIL quality and NPK fertilizers had different effects on growth and flowering. NI-R and NI-W had more pronounced effects on the growth and flowering characteristics of Phalaenopsis orchid. The negative role of 20-20-20 treatment compared to 19-6-20 could be due to the adverse effects of higher P. Among different NPK fertilizers, 19-6-20 efficiently affected physiological and morphological characteristics of Phalaenopsis orchid , but the reproductive stage was not significantly impacted by employed NPK fertilizers .

Postharvest transient water deficit limits longevity of cut Dendrobium ‘Khao Sanan’ orchid

A negative water imbalance due to a temporary water deficit (WD) after harvest can stimulate early flower senescence and reduce flower quality and vase life of orchids. To clarify the physiological responses of cut Dendrobium ‘Khao Sanan’ inflorescences under WD stress and early responses during water recovery, relative water content (RWC), water potential, reactive oxygen species (ROS), ethylene production, lipid peroxidation, antioxidant enzymes, and osmolyte were determined. The inflorescences were exposed to WD for 0, 24, 48, and 72 h after harvest, then placed in water for recovery and vase life determination. The results showed that WD significantly reduced RWC in petals, and over 24 h of WD adversely affected postharvest quality including vase life of cut inflorescences by increasing flower abscission, flower bud opening, and decreasing flower quality score. Moreover, ethylene production was induced early by 72 h of WD. Exposure of cut flowers to WD also increased hydrogen peroxide (H2O2) content, malondialdehyde (MDA) content, proline content, and lipoxygenase (LOX) activity. Additionally, ascorbate peroxidase (APX) and catalase (CAT) activities fluctuated with durations of dry and recovery periods. After rewatering, RWC, water potential, MDA content, and LOX activity of all WD periods recovered at non-WD control levels while H2O2 and proline content remained higher than control. On the other hand, ethylene production of the inflorescences exposed to WD over 24 h remarkably increased after rewatering. Our findings suggested that Dendrobium ‘Khao Sanan’ could tolerate transient WD up to 24 h with negligible reduction in longevity, probably corresponding to the lowest ethylene production during the WD period and the accumulation of antioxidant enzymes and osmolytes.