Salinity is a significant abiotic stress factor for ornamental plants cultivated in greenhouses, as they are supplied with fertilizers over a long period of time. It causes drastic yield losses in com-mercially important ornamentals such as Gerbera jamesonii, whose cut flowers rank fifth in the global flower trade. In the current study, pretreatment of G. jamesonii plants (white and yellow flowering varieties) with optimum concentrations of thiourea (1.0 mM, 5.0 mM & 10.0 mM) in-duced plant salt-tolerance. Gerberas pretreated with thiourea (5.0 mM), when exposed to NaCl (200mM), showed no signs of plant stress or phenotypic abnormalities, as seen in gerberas ex-posed to NaCl without thiourea pretreatment. Moreover, thiourea application significantly pro-moted plant growth as evidenced by increases in fresh and dry leaf weight, relative water con-tent, total protein content, free proline content, and chlorophyll. A decrease in H2O2 and MDA content and an increase in antioxidant enzymes superoxide dismutase, catalase, ascorbate perox-idase, glutathione reductase, and peroxidase activity indicate minimal cellular damage in gerberas treated with thiourea. Thus, spraying leaves with thiourea (5.0 mM) could help gerbera plants overcome the deleterious effects of salt stress during repeated fertilization in nethouses. In addi-tion to alleviating salt stress, thiourea can also be used as a biofertilizer. This could also be ex-tended to other ornamental species to promote sustainable development of the floriculture indus-try.

Cut flowers of Gerbera jamesonii, renowned globally for their vibrant colors and extended shelf life, play a pivotal role in the flourishing floriculture industry. However, repeated fertigation in nethouses/polyhouses poses a significant challenge leading to production losses. In response to this challenge, we hypothesized that the application of Ascorbic acid (AsA), an antioxidant, in optimal concentrations could alleviate the detrimental effects of salt toxicity and enhance Gerbera production. Our objective was to investigate the impact of exogenous AsA (1.0 mM, 2.0 mM, and 4.0 mM) as a foliar spray, followed by NaCl (200 mM) treatment, across two cultivars of Gerbera: white-flowered (salt sensitive) and yellow flowered (salt tolerant) cultivars. The research employed a comprehensive approach, applying AsA and NaCl treatment to evaluate their effects on chlorophyll, proline, and total soluble protein content, MDA, H2O2, and antioxidant enzyme activities (SOD, CAT, APX, GR, and POD). Following exposure to 2.0 mM AsA, treated plants displayed a notable increase in chlorophyll, Proline, and soluble protein content. Concurrently, MDA and H2O2 levels, indicator of intracellular damage, exhibited a decrement, suggesting AsA's protective role against salt stress. Moreover, enhanced antioxidant Enzyme activities were observed. The application of AsA (2.0 mM) not only induced salt tolerance in Gerbera but also showed potential benefits for its overall growth and development. This study underscores the promising role of AsA in mitigating salt-induced challenges in Gerbera cultivation.

To investigate the influence of supplemental lighting intensity on the production of cut gerbera during Canada’s supplemental lighting season (November to March), trials were carried out at a research greenhouse. Five supplemental LED light intensity (LI) treatments provided canopy-level photosynthetic photon flux densities (PPFD) ranging from 41 to 180 µmol·m-2·s-1. With a 12-h photoperiod, the treatments provided 1.76 to 7.72 mol·m-2·d-1 of supplemental light. Two cultivars of cut gerbera (Gerbera jamesonii H. Bolus ex Hook.f) were used to evaluate vegetative growth and flower production. Plugs of ‘Ultima’ were assessed for vegetative growth and rate of flower development. There were minor LI treatment effects on number of leaves and chlorophyll content index and flowers from plants under the highest vs. lowest LI matured 10% faster. Reproductively mature ‘Panama’ plants were assessed for flower yield and quality. ‘Panama’ flowers from the highest LI treatment had shorter stems than the three lowest LI treatments, flowers from the middle LI treatment had larger diameter than the other treatments. Flowers from the lowest LI treatment had lower fresh mass than the three highest LI treatments. There were linear relationships between LI and numbers of flowers harvested, with the highest LI treatment producing 10.3 and 7.0 more total and marketable flowers per plant than the lowest LI treatment. In general, increasing levels of supplemental light had only minor effects on vegetative growth (young plants) and size and quality of harvested flowers (mature plants) but flowers from plants grown under higher LIs were more numerous and matured faster.