Non-Structural Carbohydrates, Foliar Nutrients, Yield Components and Oxidative Metabolism in Pecan Trees in Response to Foliar Applications of Growth Regulators

Abstract

Foliar sprays of growth regulators have commercial potential for improving the performance of some of the parameters associated with alternate bearing in pecan trees. The objective was to evaluate the behaviour of alternate bearing through analysis of seasonal variations in buds and leaflets of non-structural carbohydrates (glucose, fructose, sucrose, and starch), mineral nutrients (N-total, P, K+, Ca2+, Mg2+, Fe2+, Cu2+, Mn2+ and Zn2+), yield components (nut weight per kilogram and kernel percentage) and oxidative metabolism (superoxide dismutase, hydrogen peroxide, catalase, guaiacol peroxidase and antioxidant capacity) in cv. Wichita pecan trees in response to foliar applications of gibberellic acid (50 mg L−1), calcium prohexadione (500 mg L−1) or thidiazuron (10 mg L−1). The experiment was of a completely randomized experimental design with five replicates. Foliar growth regulator (GRs) sprays help maintain the concentration of non-structural carbohydrates in the leaflets and buds between the evaluation years. With the exception of K+ (12.9 and 10.9 g kg−1) and Zn2+ (45.1 and 30.5 mg kg−1), the GRs did not show any effects on the concentrations of the foliar mineral nutrients. The results suggest foliar sprays of gibberellic acid improve the performance of parameters associated with alternate bearing, including oxidative metabolism.

Transcriptome-Based Construction of the Gibberellin Metabolism and Signaling Pathways in Eucalyptus grandis × E. urophylla, and Functional Characterization of GA20ox and GA2ox in Regulating Plant Development and Abiotic Stress Adaptations

“…The E. grandis × E. urophylla hybrid exhibits excellent growth rate, wood quality, and abiotic stress resistance. As GA is a multifaceted phytohormone that directly or in part regulates the abovementioned traits [ 10 , 11 , 12 , 43 ], investigation of the role of GA in Eucalyptus might help to clarify the molecular mechanism governing the formation of these economic traits and further facilitate genetic modifications. Although the genes of the main steps in GA biosynthesis, degradation, and signaling have been well studied in Arabidopsis and rice in recent decades [ 10 ], there is still a lack of integrative investigation of the whole pathway based on genomic and transcriptomic data for most species, including Eucalyptus .…”

“…Gibberellins (GAs), a class of tetracyclic diterpenoid phytohormones, play an important role in many aspects of plant growth and development, including seed germination, wood formation, flowering, and stress adaptation [ 10 , 11 , 12 ]. In the past few decades, the metabolism and signaling of GAs have been well studied in many plant species, especially in Arabidopsis and rice.…”

Evaluation of Pecan [Carya illinoinensis (Wangenh.) K. Koch] Cultivars for Possible Cultivation for Both Fruit and Truffle Production in the Puglia Region, Southeastern Italy

“…The alternate bearing could be significantly reduced in pecan trees by the application of growth regulators which can also improve the yield, as observed in Mexico for Wichita trees treated with gibberellic acid (GA 3 ), calcium prohexadione (3-oxido-4-propionyl-5oxo-3cyclohexene-carboxylate) and thidiazuron [1-phenyl-3-(1,2,3 thidiazol-5-yl) urea] [36]. A pecan evaluation of 10 cultivars in Hongzhai region of China, with an average temperature of 16.7 • C and rainfall of 1500 mm, different from Puglia climatic conditions, resulted in heavier nut (10.3 g) and kernel (5.3 g) weights as average [37].…”

Effect of foliar application of zinc on annual productivity, foliar nutrients, bioactive compounds and oxidative metabolism in pecan

“…In all formulations, 0.1% urea was added as the carrier ion and 100 mg • L −1 of Tween ® 20 (Thermo Fisher Scientific TM , Waltham, MA, USA) was used as the non-ionic surfactant. The pH of the solutions was adjusted to 6.5 with HCl to facilitate foliar uptake in formulations with metallic nutrients (Ojeda-Barrios et al, 2014). The Zn solution was applied between 0600 hr and 0900 hr, using a 25-L motorised backpack fertiliser applicator, six times per season (2019 and 2020) -on 7 April; 6, 16 and 30 May; and 11 and 26 June.…”

“…Extraction and quantification of glucose, fructose, sucrose and starch were carried out according to the method described by Ojeda- Barrios et al (2022). Briefly, a sample of 1 g of fresh tissue was taken and homogenised twice, first with 5 mL of 95% aqueous ethanol (v:v) and next with 70% aqueous ethanol (v:v).…”