Journal of Ornamental Plants
Volume:3 Issue: 3, Summer 2013

Tuberose (Polianthes tuberosa L.) is an important commercial cut flower that has a short vase life. An experiment was carried out by using five different levels of humic acid (HA) (0, 25, 50, 75, and 100 mg L-1) and seven different levels of silver nano-particles (SNP) (0, 0.5, 1, 2, 3, 4 and 5 mg L-1) mixed with 1.5% sucrose on cut tuberosa cv. Single flower. The loss of fresh weight on third and sixth days in 25 mg L-¹ HA 1.5% sucrose, 50 mg L-1 HA 1.5% sucrose and 75 mg L-1 HA 1.5% sucrose was less compared to other treatments. Also HA decreased lipid peroxidation. Silver nano-particles increased the water uptake, fresh weight, total protein, and declined lipid peroxidation compared to the control. Results showed that suitable levels of HA and SNP lead to better morphological and physiological properties and increase the vase life of cut Tuberose flower.

The effects of sodium chloride (NaCl) salinity (control; canal water with 0.4 dS m-1), 2.5 dSm-1, 5.0 dS m-1, 7.5 dS m-1 and 10.0 dS m-1, respectively) developed after 6 weeks of pruning (beginning of study) on plant growth, flowering and quality of three cut rose (Rosa hybrida L.) cultivars viz. ‘Kardinal’, ‘Angelique’ and ‘Gold Medal’ were studied to achieve better management, quality production and ascertaining salinity tolerance of promising cut roses being grown commercially in Pakistan. Plants were grown in pure sand in order to eliminate substrate salinity effect on plants. Number of leaves branch-1, leaf area, leaf total chlorophyll contents, bud diameter, flower diameter and flower quality were greater when plants were grown with canal water (control) having only 0.4 dS m-1 salinity, which also reduced interval between flushes by early flowering, while plant height, number of flowers plant-1 flush-1, fresh and dry weight of a flower, stem length and diameter were greater with 2.5 dS m-1 substrate salinity followed by canal water (control). Among cultivars, ‘Angelique’ proved comparatively more salt tolerant as compared with ‘Kardinal’ and ‘Gold Medal’ by producing vigorous growth and greater number of flowers. In summary, cut rose cultivars studied cannot tolerate higher substrate salinity and preferably be grown with

Carbon and nitrogen are the two elements that most affect plant organogenesis in vitro, usually as part of the macronutrients. Some anecdotal evidence from the literature suggests that the ammonium (NH4 ) to nitrate (NO3 –) ratio may affect orchid organogenesis. In this study, to test this hypothesis, different NH4 : NO3 – ratios were tested on the development of protocorm-like bodies (PLBs) of hybrid Cymbidium Twilight Moon ‘Day Light’, when modified in Teixeira Cymbidium (TC) No. 1 medium without plant growth regulators (PGRs). More PLBs formed per half-PLB or per PLB thin cell layer (tTCL) when TC medium was used while TC from which PGRs or NO3 – or NH4 were removed (two controls) contained significantly less PLBs/explant. The same trend was observed for neo-PLB (i.e., newly formed PLB) fresh weight. A high NO3 – ratio favoured neo-PLB formation, but always less than TC medium, but significantly higher than the two controls. tTCLs performed more poorly (i.e., fewer neo-PLBs/explant and lower fresh weight) than half-PLBs. The NH4 : NO3 – ratio can be manipulated to increase the level of PLB production in the absence of PGRs.

Gerbera jamesonii is of commercial significance and fifth most used cut flower in the world today. A pot experiment was performed to see the effect of co-inoculation of arbuscular mycorrhizal fungi (AMF) i.e. (Glomus mosseae and Acaulospora laevis) with phosphate solubilizing bacteria Pseudomonas fluorescens in the presence of different doses of superphosphate (low, medium, high) on growth establishment and flowering response of Gerbera. Among all treatments, plants inoculated with mix culture of G. mosseae A. laevis P. fluorescens showed best response in terms of greater root length, root biomass, percent root colonization, AM spore number, number of flowers, phosphorus content and phosphatase activity at lower concentration of superphosphate. Moreover, maximum increase in leaf area and shoot biomass was found in plants treated with dual combination of G. mosseae P. fluorescens at lower concentration of superphosphate. This study provides a good scope for commercially utilizing the efficient strains of AM fungi with P. fluorescens in the establishment and growth improvement of Gerbera.

The postharvest vase life of cut roses was studied to determine the effects of various physiological factors that influence the vase life of cut flower. Cut roses were obtained from commercial area of Siliguri. To assess the effect of preservatives on the postharvest life of rose, cut flowers were treated with following preservative solutions: fixed amount of citric acid (CA) (300 μg/ml) and 8-hydroxyquinoline (8-HQ) (200 μg/ml) with various concentrations (1% to 8%) of sucrose solution. Each treatment consisted of 3 replicates. Cut roses were treated with different solutions and were kept at normal room temperature (20° C) under normal day light and natural ventilation. The biochemical parameters such as phenol, flavonol content, total soluble sugar, reducing sugar, non-reducing sugar, and for antioxidant property 1,1-diphenyl-2- picrylhydrazyl (DPPH) free radical scavenging activity was determined in flowers treated for 0, 2, 4, 6 and 8 days, respectively. The physiological parameters such as vase life, water uptake, transpiration rate and water balance were also observed. The results demonstrated that the flowers which were treated with 5% of sucrose extended the vase life of cut flower from 4 to 8 days by improving the carbohydrate supply and reducing oxidative stress mediated damages during rose flower senescence.

Nitric oxide (NO) is a highly reactive signaling molecule and plays a variety of physiological roles in plants. The research on the application of NO to postharvest preservation of flowers and fruits shows great promise in recent years. However, the physiological mechanism of exogenous NO to affect cut flowers is not very clear, and NO donor treatment protected plants from damage by increasing the activity of antioxidative enzymes. Therefore, an experiment was conducted to study the effect of exogenous NO on the vase life and physiological basis of Dianthus caryophyllus L. ‘Tempo’. The presence of the nitric oxide increased the activities of POD, while the production of MDA content and LOX activity were obviously decreased. The results showed that exogenous NO could significantly extend the vase life of cut carnation flowers (16.9 days). The results suggest that exogenous NO could delay petal wilting in carination cut flowers, maintain water metabolism, the antioxidative enzymes activity and mass-eliminate reactive oxygen species (ROS) and as well as cell membrane stability.

In our study, bioactivity of essential oil extracted from Ginger (Zingiber officinale Roscoe.) that belongs to family Zingiberaceae was analyzed. Ginger rhizome oil was found to be effective against a range of bio-deteriogens. The Minimum Inhibitory Concentration (MIC) value was determined by Poisoned Food Technique and Volatile Activity Assay. The study demonstrates that essential oil had a wide spectrum of antifungal activities against common biodeteriogens Aspergillus niger van Tiegh., Penicillium chrysogenum Thom., Alternaria alternata (Fr.) Keissl and Fusarium roseum Link. Minimum inhibitory concentration (MIC) of oil was found to be effective, showing results at 1.0 μL/cm-3of oil in respect to all fungi. At higher concentration of 2.0 μL/cm-3 of oil was fungicidal in action. 2.0 μL/cm-3 was proved appropriate concentration for commercial trial of ginger oil as preservative for stored pulses and nuts which were used as test commodities.

The effect of electromagnetic field was examined on Zinnia (Zinnia elegans) seeds to enhance seed germination and early growth. The seeds were exposed to four magnetic strengths of 15, 100, 400 and 800 μT in four durations of 30, 60, 120 and 240 min. The experiments were carried out in two forms of laboratory germination and soil emergence. Results showed that magnetic field application enhanced seed performance in both terms of laboratory germination and soil emergence. The magnetic field significantly (p≤0.05) affected root length, shoot length, fresh and dry root weight, fresh and dry shoot weight, seedling length and weight, germination percentage, speed of germination, vigor index I and II in laboratory germination. Also, the magnetic field exposure significantly affected soil emergence factors of root length, shoot length, dry root weight, dry shoot weight, seedling length, emergence percentage and emergence speed at 0.05 level of probability. The other factors were significantly (p≤0.05) different compared with unexposed control. No significantly differences were found on the interaction of time and exposure field. The best results were found to 400 μT (micro Tesla) on seed germination and seed emergence. The exposure durations of 240 and 30 min showed promising results over all magnetic fields in seed germination and emergence, respectively. However, there was no significant difference among exposure times.