Leaf Net Photosynthesis, Leaf Greenness, and Shoot Lignin Content of Nonbearing Pecan Trees at Two Nitrogen and Nickel Application Rates

Abstract

<jats:p>In recent years, nickel (Ni) deficiency symptoms has been observed in commercial pecan [<jats:italic>Carya illinoinensis</jats:italic> (Wangenh.) K. Koch.] orchards in New Mexico. Nickel deficiency can cause a reduction in lignin formation, which could affect the risk for breakage on pecan tree shoots. Ni deficiency might furthermore disrupt ureide catabolism in pecan and, therefore, could negatively affect nitrogen (N) nutrition in the plant. The objective of this study was to identify the effects of Ni and N fertilizer applications, at two rates, on net photosynthesis (P<jats:sub>n</jats:sub>), leaf greenness (SPAD), and branch lignin concentration in New Mexico’s nonbearing pecan trees. Sixty trees for year 2012 (Pawnee and Western cultivars) and 40 trees for year 2013 (Pawnee cultivar) were used at two New Mexico locations (Artesia and Las Cruces) to evaluate the effects of Ni and N on tree measures. Treatments were as follows: (1) High N plus Ni (+Ni); (2) Low N no Ni (−Ni); (3) High N −Ni; and (4) Low N +Ni. In 2012 and 2013, there was an increase in leaf greenness for each location and cultivar (tree group) through time (June to September). Photosynthesis measures in 2012 differed between tree group, time in the season, and N and Ni treatments. In 2013, P<jats:sub>n</jats:sub> was influenced by tree group and time (<jats:italic>P</jats:italic> &lt; 0.0001), but N and Ni interaction did not present a significant effect related to Ni benefits. Photosynthesis varied over time in 2012 and 2013, with an inconsistent pattern. In this study, Ni application at the high N rate had a negative effect on ‘Pawnee’ P<jats:sub>n</jats:sub> early in the season at the Artesia site, but this application had a positive effect for ‘Western’ from Artesia at the low N level, also early in the season. Lignin content varied between tree groups only. The application of N and Ni did not affect lignin in pecan shoots. The results show an inconsistent pattern regarding the benefits of Ni on nonbearing pecan orchards for leaf greenness, P<jats:sub>n</jats:sub>, and lignin content during the 2-year study. Future studies on Ni should focus on pecan trees exhibiting leaf Ni deficiency symptoms or on soils with less than 0.14 mg·kg<jats:sup>−1</jats:sup> of DTPA extractable Ni, as well as the long-term effect of Ni on pecan growth and development to optimize the addition of Ni into an efficient fertilization program.</jats:p>

Do foliar applications of nickel increase urease activity and nutrient levels in pecan leaflets?

“…In our study, a LA value of 27.28 ± 2.20 cm 2 was obtained with Ni-EDDHA and 22.85 ± 1.51 cm 2 with Ni-sulphate (Table 2). These results are in contrast with previous studies by Wagle et al (2011) and Moran-Duran et al (2020) with cv. Pawnee trees (8 and 3 years old, respectively) with foliar applications of Ni-sulphate (0.78 mL/L, 0.055 g/L and 82.3 g/ha) and 1.9 mL/L of Nickel plus® (nickel lignosulfonate).…”

“…K. Koch] is a valuable commercial crop of high nutritional value. The United States of America and Mexico together produce about 90% of the world's supply of harvested nuts (Moran-Duran et al 2020). Ensuring an adequate supply of nickel (Ni) is one of the most important management objectives for pecan trees (Ojeda-Barrios et al 2016).…”

“…However, Ni 2+ deficiency inhibits the activity of urease and so reducing the conversion of urea to NH 4 + ions and potentially inducing chlorosis and even necrosis of the leaflets. In addition, Ni 2+ deficiency is also associated with the visual symptom "mouse ear", which arises from a disruption of amino acid metabolism and the citric acid cycle (de Queiroz- Barcelos et al 2017, Moran-Duran et al 2020. Urease is a ubiquitous enzyme that contains two Ni 2+ ions in its structure in its active site (Lucasynski-Carlim et al 2019, Hernández-López et al 2020.…”

Response of Nitrogen Metabolism in Masson Pine Needles to Elevated CO2

“…Noteworthily, the previous studies have shown that the nitrogen fixation ability and the changes of nitrogen in plants are also affected by soil fertility [51,52], soil microorganisms [53,54] or metal elements [55]. We studied the change of elevated CO 2 content as the main factor but did not verify or discuss the influence of other factors on nitrogen metabolism of Masson pine under the same condition.…”