Effects of Zn Deficiency and Bicarbonate on the Growth and Photosynthetic Characteristics of Four Plant Species

Abstract

Calcareous soils are characterized by low nutrient contents, high bicarbonate (HCO3−) content, and high alkalinity. The effects of HCO3− addition under zinc-sufficient (+Zn) and zinc-deficient (−Zn) conditions on the growth and photosynthetic characteristics of seedlings of two Moraceae species (Broussonetia papyrifera and Morus alba) and two Brassicaceae species (Orychophragmus violaceus and Brassica napus) were investigated. These four species were hydroponically grown in nutrient solution with 0 mM Zn (−Zn) or 0.02 mM Zn (+Zn) and 0 mM or 10 mM HCO3−. The photosynthetic response to HCO3− treatment, Zn deficiency, or both varied according to plant species. Of the four species, Broussonetia papyrifera showed the best adaptability to Zn deficiency for both the 0 mM and 10 mM HCO3− treatments due to its strong growth and minimal inhibition of photosynthesis and photosystem II (PS II). Brassica napus was sensitive to Zn deficiency, HCO3− treatment, or both as evidenced by the considerable inhibition of photosynthesis and high PS II activity. The results indicated different responses of various plant species to Zn deficiency and excess HCO3−. Broussonetia papyrifera was shown to have potential as a pioneer species in karst regions.

Photosynthetic characteristics and productivity in a wheat–maize system under varying zinc rates

“…In this study, Zn application significantly increased the Pn and LAI of crops, although these effects mainly depended on increases in shoot Zn concentrations, the results of which were consistent with those of previous experiments (Fernàndez, Zacchini, & Fleck, 2012; Zhao & Wu, 2017). However, the response of the Pn and LAI to shoot Zn concentration may be different depending on the crop species.…”

Elevated Root-Zone Dissolved Inorganic Carbon Alters Plant Nutrition of Lettuce and Pepper Grown Hydroponically and Aeroponically

“…Zn influences many biological processes, including carbohydrate metabolism and cell proliferation, and is an integral component of some enzyme structures, such as carbonic-anhydrase, alcohol dehydrogenase, and glutamate dehydrogenase [16]. Although photosynthetic and growth responses to Zn deficiency differ between species, meaning that some plants adapt better to such conditions [9], Zn deficiency rapidly inhibited plant growth and development, and photosynthesis of many plants, including rice [17] and spinach [18]. Zn deficiency restricts growth of lettuce plants, with necrotic spots with a dark margin appearing later along leaf edges [19].…”

“…However, there is little consensus on the mechanisms by which root-zone CO 2 concentration affects growth. High concentrations of HCO 3 − in the soil can decrease plant productivity, particularly in soils with low bioavailability of plant nutrients, high Ca content and high alkalinity [9,10]. In calcareous soils with high pH (>7), the availability of Fe and other essential micronutrients such as Zn, Mn, and Cu are usually low due to their precipitation as oxides or carbonates [10].…”

Green fabricated zinc oxide nanoformulated media enhanced callus induction and regeneration dynamics of Panicum virgatum L.

“…Additionally, Zn deficiency hindered the plant bicarbonate use capability and PS II activity due to the incidence of excess bicarbonate ions. Zn deficiency represses other Zn-containing enzymes, such as alcohol dehydrogenase and glutamate dehydrogenase, consequently inhibiting plant growth [48].…”