Rootstock Effect on Grafted Tomato Transplant Shoot and Root Responses to Drying Soils

Abstract

Improvement of crop water use is imperative. Plants' responses to limited water can dictate their ability to better use available resources and avoid prolonged and severe stress. The following study was conducted to determine how tomato (Solanum lycopersicum) rootstocks with different root system morphologies respond to drying soils. Plants were grown in pots containing an inorganic substrate composed of calcined clay and sand in a greenhouse on North Carolina State University's campus. The heirloom tomato cultivar Cherokee Purple was used as the scion for 'Beaufort' and 'Shield' rootstocks as well as the self-grafted control. These rootstocks were assigned either normal or reduced irrigation treatments. Plants grown under the normal irrigation schedule were weighed and watered daily to maintain container capacity for one week. Those receiving reduced irrigation had all water withheld for one week, at which point strong midday wilting became evident. Shoot physiological and morphological data as well as root morphological data were collected at the end of the study. A constitutive positive increase on relative water content, leaf area, stomatal conductance (g S ), and net CO 2 assimilation rate was observed with scions grafted on 'Beaufort'. In addition, this rootstock had a significantly longer total root system (118.6 m) compared with 'Shield' (94.9 m) and the self-grafted control (104.2 m). Furthermore, 76.4% of the total root length observed in 'Beaufort' was composed of very thin diameter roots (; <0.5 mm), which was higher than 'Shield' (73.67%) and the self-grafted control (69.07%). The only significant rootstock 3 irrigation interaction observed was for effective quantum yield of photosystem II (u PSII ). At normal irrigation there were no differences among the rootstock treatments; however, at reduced irrigation 'Beaufort' had significantly higher u PSII than both 'Shield' and the self-grafted control. These results may explain some of the improved production and water use efficiency observed in field trials using 'Beaufort' rootstock, and data secured may allow for better screening of rootstocks for improved water use efficiency in the future.

Nitrogen Accumulation and Root Distribution of Grafted Tomato Plants as Affected by Nitrogen Fertilization

“…Such differences reflected the potential of vigorous rootstocks to enhance the growth of grafted plants. The results are consistent with those of previous reports of grafted tomato (Di Gioia et al, 2010;S anchez-Rodríguez et al, 2014;Suchoff et al, 2018a). Neocleous (2015) reported greater dry biomass for shoots of grafted than of nongrafted melon plants and suggested the involvement of increased photosynthetic capacity associated with biochemical functions at the chloroplast level.…”

“…Tomato root density and number of root hairs were significantly improved when grafted plants were compared with self-grafted plants grown in perlite substrate (Oztekin et al, 2009). Using a greenhouse pot study, Suchoff et al (2018a) also detected a significant increase in total root length and more finer roots in tomato plants grafted with 'Beaufort' than the self-grafted control. Conversely, Miller et al (2013) did not find differences in root length density (RLD) between grafted and nongrafted watermelon during a 3-year field study.…”

Effect of Self- and Inter-Cultivar Grafting on Growth and Nutrient Content in Sweet Basil (Ocimum basilicum L.)

“…Among limited information, enhanced water and nutrient uptake and use efficiency by grafting have been reported in cucurbits ( Nawaz et al, 2017 ; Liang et al, 2021 ) and solanaceous crops ( Leonardi and Giuffrida, 2006 ; Albornoz et al, 2018 ). This enhanced uptake is often attributed to improved root system size and architecture ( Huang et al, 2016 ; Suchoff et al, 2018 ; Liang et al, 2021 ) or more efficient nutrient transporters ( Albornoz et al, 2018 ).…”

Evaluating Ethylene Sensitivity and Exogenous Ethylene Impact on Early Growth of Grafted and Nongrafted Tomato Seedlings

“…This indicates the grafted plants may have improved tolerance to the exogenous ethylene treatments compared with the nongrafted plants. Tomato rootstocks could provide improved stress tolerance, which has been demonstrated in grafted plants subjected to heat stress (Rivero et al, 2003) and water stress (Suchoff et al, 2018). Also, it is well documented that plants preconditioned to stress can have improved stress tolerance to secondary stress (Dong et al, 2013;Ghanbari and Sayyari, 2018;Zhang et al, 2018).…”