Greenhouse Mist Improves Yield of Tomato Plants Grown under Saline Conditions

Abstract

<jats:p>High salinity levels in irrigation water available in Mediterranean coastal areas induce a significant loss of yield in greenhouse tomato crops. This loss increases during the spring-summer growing season when high irradiance, temperature, and low humidity occur within greenhouses. This study determined whether salt-induced yield losses could be alleviated by increasing humidity by misting the greenhouse atmosphere. Plants of `Daniela' tomato (<jats:italic>Lycopersicon esculentum</jats:italic> Mill.), were irrigated with 0 or 50 m<jats:sc>m</jats:sc> NaCl added to the nutrient solution and grown under natural greenhouse conditions or under applications of fine mist every 8 min during the day. During midday hours, misting reduced greenhouse air vapor pressure deficit 1.0 to 1.5 kPa and reduced greenhouse air temperature 5 to 7-°C. Mist reduced root water uptake from the medium by 40% in nonsalinized plants and by 15% in saline conditions. Foliar concentration of Na was lower in misted-salinized plants than in nonmisted salinized plants. Less negative leaf water potential and higher leaf turgor were recorded with mist at midday, in both salinized and nonsalinized plants. Midday stomatal conductances and net CO<jats:sub>2</jats:sub> assimilation rates of salinized-misted plants were 3 and 4 times higher, respectively, than those recorded in salinized-nonmisted plants. Misted plants increased instantaneous water use efficiency 84% to 100%, as estimated from the ratio of net CO<jats:sub>2</jats:sub> assimilation to transpiration. Nonsalinized plants grown with mist increased total leaf area by 38%, dry matter by 10%, and yield by 18% over nonmisted plants. Salinized plants grown with mist increased total plant leaf area by 50%, dry matter by 80%, and yield by 100%. Greenhouse misting resulted in a saving of total water input of 31 L/plant under nonsaline conditions and in greater yields and fruit size regardless of salinity. Results suggest that greenhouse misting, during the Mediterranean spring-summer growing season, improves tomato crop productivity both under nonsaline and saline growth conditions.</jats:p>

Tomato fruit continues growing while ripening, affecting cuticle properties and cracking

“…RH also influenced fruit growth during ripening, because higher rates of fruit growth can be observed under high RH. These results are in agreement with previous reports on the role of RH on fruit growth (Romero‐Aranda et al 2002, Kawabata et al 2005, Génard et al 2007). This effect of radiation and RH on fruit growth rate is mostly due to changes in the growth period between mature green and light orange, because no significant changes in growth rate could be observed between light orange and overripe.…”

Effects of relative humidity and nutrient supply on growth and nutrient uptake in greenhouse tomato production

“…In our experiment, the relative humidity in G c remained at approximately 80%, but was 4.2-9.2% higher from 10:00 to 13:00 in G m than in G c . The increase tendency in DW of fruits per plant under high humidity (misting) is in agreement with other reports (Romero-Aranda et al, 2002;Dannehl et al, 2012). DW of leaves, stems and fruits showed slightly increased tendencies under mist in our experiment (Table 2).…”

Atmospheric humidity and genotype are key determinants of the diurnal stomatal conductance pattern

“…The increased g s of wheat genotypes in response to higher humidity is consistent with previous studies in other plants, such as Vicia faba (Romero‐Aranda, Soria, & Cuartero, ; Talbott et al, ). But genotypes differ in the magnitude of g s under different RH and in the increased magnitude with LRH changing to HRH.…”

“…ity is consistent with previous studies in other plants, such as Vicia faba(Romero-Aranda, Soria, & Cuartero, 2002;Talbott et al, 2003).But genotypes differ in the magnitude of g s under different RH and in the increased magnitude with LRH changing to HRH. Of the 11 comparable genotypes, Jinmai 47, Yanzhan 4110 and Yumai 18 were distinctive.…”