Foliar Application of Growth Bioregulators Influences Floral Traits, Corm- associated Traits and Chemical Constituents in Gladiolus grandiflorus L.

Abstract

Gladiolus is one of the most popular cut flowers in the world floral market and is highly attractive to consumers. The production of poor-quality gladiolus spikes is one of the most important hurdles to obtaining high prices for this crop. The main objectives of this study were to improve the quantitative characteristics of gladiolus spikes, to increase propagule production and to enhance chemical constituent levels in leaves to help improve plant growth. We performed foliar application of bioregulators, including polyamines (putrescine and spermine) and vitamins (ascorbic acid and thiamine), at different concentrations (0, 0.1, 0.4, 0.7 and 1 mM) to gladiolus plants at the three leaf, five leaf and slipping stages. Application of 1 mM putrescine was the most effective treatment, with prominent effects on economically important spike traits including spike length (55.53 cm), spike diameter (7.53 mm), florets per spike (13.99), first floret diameter (9.66 cm) and first floret weight (4.90 g), followed by spermine treatment. The 1 mM putrescine treatment also had positive effects on corm-associated traits including corm diameter and corm weight, with values of 4.57 cm and 26.16 g compared to 3.47 cm and 17.16 g in control plants, respectively. The contents of chemical constituents in leaves, including total chlorophylls (8.06 mg･g -1 ), total carotenoids (1.66 mg･g -1 ), total soluble sugars (4.75 mg･g -1 ) and phenolics (0.89 mg･g -1 ) increased in response to foliar application of 1 mM putrescine compared to the control. Ascorbic acid and thiamine also had positive effects on various plant morphological traits and chemical constituents in leaves compared to control plants, but the growth-promoting effects of polyamines were more pronounced. Hence, applying polyamines to gladiolus leaves will help improve spike production and increasing propagule (cormel) yields.

Foliar Application of Thiamin Stimulates the Growth, Yield and Biochemical Compounds Production of Coriander and Fenugreek

“…In line with previous studies on syngonium (Abd El-Aziz et al 2007), gladiolus (Hashish et al 2015;Sajjad et al 2015) and tomato (Farouk et al 2012), Th application increased the nutrient contents in coriander and fenugreek. In a study on sunflower, the contents of toxic ions Na + , Ca2 + and Clwere significantly lower, while cytoplasmic K + content, which is essential for survival in stress condition, were higher in Th-treated plants (Sayed & Gadallah 2002).…”

“…Reda et al (2005) demonstrated that the application of Th at 60 ppm resulted in higher content of total phenolics in thyme. Similar results were obtained on gladiolus, where phenolics increased in response to Th foliar application (Sajjad et al 2015). Results of El-Bassiouny and Sadak (2015) in Linum usitatissimum also revealed that vitamins, ascorbic acid and α-tocopherol induced considerable reduction in lipid peroxidation but an increase in superoxide dismutase as an antioxidant.…”

“…Th is also involved in tolerance to DNA damage (Raschke et al 2007). In addition, the exogenous application of Th increases the plant resistance against biotic and abiotic stresses such as salinity, extreme temperatures and plant pathogens (Bahuguna et al 2012).The positive impact of Th has been previously proved on growth, yield, photosynthesis rate and nutrients, pigments, oil and protein contents in many plants such as Lupinus termis (El-Awadi et al 2016), Vicia faba (Hamada & Khulaef 2000), Gladiolus grandiflorus (Sajjad et al 2015;Hashish et al 2015), Matricaria recutita (Ranjbar et al 2014), Thymus vulgaris (Reda et al 2005), Calendula officinalis (Soltani et al 2014) and Ocimum basilicum (Fallahi et al 2018). However, there is no scientific report about the foliar application of Th in the two multipurpose species, fenugreek and coriander.…”

Response of Tuberose (Polianthes tuberosa L.) cv. Pajwal to Flower Inducing Chemicals

“…Increase in floret weight spike -1 with GA 3 was attributed to the production of more number of bigger size florets as gibberellins are important for differentiation and growth of more number of flower primordia (Alpi et al, 1976). These results are in line with the findings of Sajjad et al, (2015) in gladiolus.…”

Effects of 1-Naphthaleneacetic Acid on the Panicle and Fruit Characteristics of ‘Irwin’ Mango Trees

“…One such compound is 1-naphthaleneacetic acid (NAA), which is a synthetic auxin that plays multiple roles in regulating vegetative and reproductive growth. It is considered safe for plants at recommended concentrations and has been used in tissue culture and fruit thinning (Sajjad et al, 2015;Yoo et al, 2016;Tepkaew et al, 2022). As a growth regulator, NAA affects plant reproduction, including panicle development (Jain and Khurana, 2009).…”