Location: Fruit and Tree Nut ResearchTitle: Effects of Foliar Applications of Zinc and Nickel Nano-Fertilizers vs Conventional Fertilizers on Plant Physiology in Pecan [Carya illinoinensis (Wangenh.) K. Koch] cvs. ‘Zinner’ and ‘Byrd’
|ROSSI, LORENZO - University Of Florida|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 3/10/2020
Publication Date: N/A
Interpretive Summary: Abstract Only.
Technical Abstract: Micronutrients, such as nickel (Ni) and zinc (Zn), are critical to maximize pecan [Carya illinoinensis (Wangenh.) K. Koch] tree health and play important roles in fruit set and retention, as well as nut yield and nutmeat quality. A greenhouse study was conducted with the aim to gain more knowledge about plant growth, physiology, and uptake of two micronutrients (Zn and Ni) in pecan plants exposed to foliar applications of conventional fertilizers (ZnSO4, NiSO4) and nano-fertilizers (Zn-NPs, Ni-NPs). Two-year-old pecan plants of cvs. ‘Zinner’ and ‘Byrd’ grafted onto cv. ‘Elliott’ were treated with 5 foliar applications of 25 mg/L ZnSO4·H2O or Zn-NPs, and 10 mg/L NiSO4·6H2O or Ni-NPs and compared to untreated control plants over the course of 45 days. Differences were observed between cultivars and among treatments. Net photosynthetic rate was higher in nickel-treated nano-fertilized ‘Zinner’ plants. Ni-NPs-treated leaves contained significantly higher amounts of Ni (5.07 ± 0.76 mg/kg DW cv. ‘Zinner’ and 7.07 ± 1.14 mg/kg DW cv. ‘Byrd’) when compared to NiSO4-treated leaves (2.93 ± 0.37 mg/kg DW cv. ‘Zinner’ and 4.46 ± 0.77 mg/kg DW cv. ‘Byrd’). In addition, chlorophyll content (SPAD reading) of Ni-treated plants was highest in control (43.06 ± 4.14) and NiSO4-treated plants (41.87 ± 6.10) of cv. ‘Byrd’. No differences between cultivars or among treatments were observed in fresh and dry weights of leaves. Fluorescence data (Fv/Fm ratio) showed differences among days after initial treatment for both cultivars (P < 0.0001 for ‘Zinner’ and P = 0.0023 for ‘Byrd’) and among treatments for cultivar ‘Zinner’ (P = 0.0075). Differences for leaf area were observed among the two cultivars of Ni-treated and Zn-treated plants (P < 0.0001). Overall, Ni-NPs were more easily absorbed into the leaf than regular Ni fertilizers for both cultivars and Ni-NPs showed a positive impact on gas exchange parameters such as net carbon assimilation rate, transpiration rate, and stomatal conductance on plants of cv. ‘Zinner’. Nano-fertilizers could potentially replace or supplement traditional salt-based fertilizers and could be very applicable in pecan systems. A field study is needed to confirm our greenhouse observations.