Slight vapor deficit accelerates graft union healing of tomato plug seedling
The application of grafting in tomato production has substantially improved tomato quality and yields. It has been demonstrated that humidity plays an important role in the graft healing of seedlings. This study focuses on the optimum relative humidity (RH) conditions for scion and rootstock healing of grafted tomato (Solanum lycopersicum L.) seedlings. Two tomato cultivars, ‘Super Sunload’ and ‘Super Dotaerang’, grafted onto ‘B-Blocking’ rootstock were subjected to one of three RH regimens: 70–80, 80–90, or 90–100%. The results showed that the scions of both cultivars showed apparent wilting under the 70–80 and 80–90% RH treatments. On this basis, the 90–100% RH treatment was subdivided into 95–96, 97–98, and 99–100% RH treatments, which were then applied. Among these subdivided RH treatments, the fresh weights of the scions and rootstocks significantly increased in response to the treatments of 97–98 and 99–100% RH, and the graft union connection of both cultivars was also enhanced after two days of healing. Furthermore, lower levels of endogenous H2O2 and less activity of antioxidant enzymes were observed in both cultivars in response to treatment with 95–96 or 97–98% RH, which indicated that less oxidative stress occurred. Overall, it is suggested that 97–98% is the optimal RH level for the graft healing of tomato seedlings.
KeywordsAntioxidant enzymes Grafting Oxidative stress Reactive oxygen species Union hardness Vascular connection
This study was carried out with support from the Korea Institute of Planning and Evaluation for Technology in Food, Agriculture, Forestry and Fisheries (Project no. 312034-4). Hao Wei, Sowbiya Muneer, Abinaya Manivannan, Ya Liu, and Ji Eun Park were supported by a scholarship from the BK21 Plus Program, Ministry of Education, Republic of Korea during the study period.
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