Plant growth and water economy of Solanum tuberosum in response to doubled CO₂: Interaction between potassium and phosphorus

Abstract

Potassium (K) and phosphorus (P) are essential macronutrients for potato (Solanum tuberosum L.); they play crucial roles in photoassimilate production that can also be affected by elevated atmospheric CO2 concentration (e[CO2]). However, the interactive effects of K and P nutrition under e[CO2] in potato have not been investigated. A pot experiment was carried out on potato plants in 1‐L pots with five K supply rates at two P supply rates in controlled‐environment chambers with ambient CO2 concentrations (a[CO2]) and an e[CO2] level of double a[CO2]. There was a significant interaction between K supply and P supply, but not between CO2 and K supply on total plant biomass, water use as well as water‐use efficiency (WUE). K supply could remarkably enhance the accumulation of plant biomass under e[CO2] by promoting tuber formation. The maximum total plant biomass increased by approximately 1.3‐fold under e[CO2] in this study, while the effect of CO2 was dependent on both P and K supply. Additionally, WUE was increased by e[CO2] and P and K supply. Both CO2 enrichment and K supply increased WUE by stimulating biomass accumulation and reducing water consumption. We concluded that the CO2‐fertilization effect and WUE were dependent on both P and K supply. Less biomass accumulation in response to K supply in plants with P deficiency indicates that a balanced nutrient status is crucial for crop production under e[CO2].

Verification of water‐use efficiency estimates via carbon isotope discrimination in potato under varying nutrient statuses and CO2 conditions

“…( n = 5 or 6 [in Trial P] or 4 [in Trials N and K] biological replicates for each treatment). Data for biomass, water use and WUE in Trials P, N, and K were reused from Yi et al (2019, 2020) and Yi and Yano (2021)…”

“…(n = 5 or 6 [in Trial P] or 4 [in Trials N and K] biological replicates for each treatment). Data for biomass, water use and WUE in Trials P, N, and K were reused from Yi et al (2019Yi et al ( , 2020 and Yi and Yano (2021) significantly different (Table 4). Furthermore, a common slope was observed in Trials P and K, which was slightly different from that in Trial N (Table 4).…”

“…Previous studies have demonstrated negative correlations between Δ 13 C and WUE under aCO 2 in various species, such as barley (Hubick & Farquhar, 1989), peanut (Hubick et al, 1986; Wright et al, 1994), cowpea (Ismail & Hall, 1992), wheat (Arslan et al, 2008), legumes (Berriel et al, 2019), grapevines (Bchir et al, 2016), tomatoes (Martin et al, 1999), and potatoes (Jefferies, 1995; Monneveux et al, 2013; Ramírez et al, 2016), in which soil water conditions were the cause of variations in WUE. While these previous studies focused on aCO 2 , it was reported that eCO 2 led to higher WUE without changing Δ 13 C (Beerling & Woodward, 1995; Polley et al, 1995), whereas WUE under eCO 2 showed complicated patterns of interaction with nutrition (Igarashi et al, 2021; Yi & Yano, 2021; Yi et al, 2019, 2020). These results suggest the importance of examining the relationship between WUE and Δ 13 C, especially during the interaction between CO 2 and nutritional status; however, this knowledge is almost missing in the literature.…”

“…In wheat, water consumption was smaller under eCO 2 despite a 2.2‐fold greater biomass because of more than doubled WUE compared to aCO 2 (Igarashi et al, 2021). In addition, WUE under eCO 2 was more variable than that under aCO 2 according to nutrient supply (Igarashi et al, 2021; Yi & Yano, 2021; Yi et al, 2019, 2020), although WUE has been regarded as very conservative (Sinclair et al, 1984; Tanner & Sinclair, 1983). These results imply that under eCO 2 compared to aCO 2 : (1) higher WUE may reduce plant water demand, (2) WUE may become more critical for biomass production than transpiration, and (3) the WUE may become more dependent on nutritional status.…”

Revisiting Why Plants Become N Deficient Under Elevated CO2: Importance to Meet N Demand Regardless of the Fed-Form

“…In addition, we paid special attention to the water-use efficiency (WUE) at the individual plant level (i.e., biomass production per transpiration). This is because an increase in plant biomass is more likely responsible for WUE rather than the amount of water transpired under eCO 2 (Yi et al, 2019 , 2020 ; Yi and Yano, 2021 ), which hardly occurs under current aCO 2 treatments except an improvement in nocturnal transpiration (Coupel-Ledru et al, 2016 ). In this study, we aimed to explore how to improve eCO 2 -induced N-limitation by answering the above questions.…”