Inhibition of tomato shoot growth by over‐irrigation is linked to nitrogen deficiency and ethylene

Abstract

Although physiological effects of acute flooding have been well studied, chronic effects of suboptimal soil aeration caused by over-irrigation of containerized plants have not, despite its likely commercial significance. By automatically scheduling irrigation according to soil moisture thresholds, effects of over-irrigation on soil properties (oxygen concentration, temperature and moisture), leaf growth, gas exchange, phytohormone [abscisic acid (ABA) and ethylene] relations and nutrient status of tomato (Solanum lycopersicum Mill. cv. Ailsa Craig) were studied. Over-irrigation slowly increased soil moisture and decreased soil oxygen concentration by 4%. Soil temperature was approximately 1°C lower in the over-irrigated substrate. Over-irrigating tomato plants for 2 weeks significantly reduced shoot height (by 25%) and fresh weight and total leaf area (by 60-70%) compared with well-drained plants. Over-irrigation did not alter stomatal conductance, leaf water potential or foliar ABA concentrations, suggesting that growth inhibition was not hydraulically regulated or dependent on stomatal closure or changes in ABA. However, over-irrigation significantly increased foliar ethylene emission. Ethylene seemed to inhibit growth, as the partially ethylene-insensitive genotype Never ripe (Nr) was much less sensitive to over-irrigation than the wild type. Over-irrigation induced significant foliar nitrogen deficiency and daily supplementation of small volumes of 10 mM Ca(NO3 )2 to over-irrigated soil restored foliar nitrogen concentrations, ethylene emission and shoot fresh weight of over-irrigated plants to control levels. Thus reduced nitrogen uptake plays an important role in inhibiting growth of over-irrigated plants, in part by stimulating foliar ethylene emission.

Experimental Study on the Potential Use of Bundled Crop Straws as Subsurface Drainage Material in the Newly Reclaimed Coastal Land in Eastern China

“…This is consistent with the research findings that subsurface drainage affected root length density (RLD) along the soil depth [49,50]. In Figure 6a, RLD reached the maximum in the top 20 cm and the minimum in 40-60 cm in all treatments.…”

Wetlands for the Treatment of Agricultural Drainage Water

“…As displayed in Figure 6, maize grown in the lysimeters with subsurface drainage had greater root growth as compared to that in CK. This is consistent with the research findings that subsurface drainage affected root length density (RLD) along the soil depth [49,50]. In Figure 6a, RLD reached the maximum in the top 20 cm and the minimum in 40-60 cm in all treatments.…”

“…To describe the temperature response of denitrification, we used Arrhenius equation, which is most commonly used in this case and where the temperature has a stronger effect on the denitrification at lower temperatures [4,47]. Several authors have reported that denitrification has a "breakpoint" temperature, below which denitrification rates decrease more rapidly [9,48,49]. The exact temperature of the breakpoint is not known, but, in most of the studies, it varies usually between 10 and 12 • C [50].…”

“…Similar to Mn, the uptake and translocation of Zn was also inhibited by Fe in the solution [47,48]. Mn, Zn, or Cu deficiency may be induced following excessive Fe fertilization due to uptake of relatively large amounts of Fe [49]. Hayes et al [48], showed a negative relationship between leaf Mn and total soil P concentration along a bay in western Australia.…”

Variable Rate Precision Irrigation Technology for Deficit Irrigation of Processing Tomato

“…Moreover, there are endangered subsurface aquifers in the country where growers cannot cover their irrigation water needs from surface water and water saving is a priority in these areas (Biró et al, 2011). Over-irrigation will lead to deep percolation or surface runoff, moreover it can also cause ponding on the surface (Fiebig and Dodd, 2016). Water and energy conservation with a positive impact on crop water productivity and the environment is achievable with site-specific irrigation (Evans et al, 2013).…”