Role of Grafting in Resistance to Water Stress in Tomato Plants: Ammonia Production and Assimilation
- PDF / 425,885 Bytes
- 12 Pages / 595.276 x 790.866 pts Page_size
- 28 Downloads / 174 Views
Role of Grafting in Resistance to Water Stress in Tomato Plants: Ammonia Production and Assimilation Eva Sa´nchez-Rodrı´guez • Luis Romero Juan Manuel Ruiz
•
Received: 5 September 2012 / Accepted: 23 April 2013 Ó Springer Science+Business Media New York 2013
Abstract In general, drought depresses nutrient uptake by the root and transport to the shoot due to a restricted transpiration rate, which may contribute to growth limitation under water deprivation. Moreover, water stress may also restrict the ability of plants to reduce and assimilate nitrogen through the inhibition of enzymes implicated in nitrogen metabolism. The assimilation of nitrogen has marked effects on plant productivity, biomass, and crop yield, and nitrogen deficiency leads to a decrease in structural components. Plants produce significant quantities of NH4? through the reduction of NO3- and photorespiration, which must be rapidly assimilated into nontoxic organic nitrogen compounds. The aim of the present work was to determine the response of reciprocal grafts made between one tomato tolerant cultivar (Lycopersicon esculentum), Zarina, and a more sensitive cultivar, Josefina, to nitrogen reduction and ammonium assimilation under water stress conditions. Our results show that when cv. Zarina (tolerant cultivar) was used as rootstock grafted with cv. Josefina (ZarxJos), these plants showed an improved N uptake and NO3- assimilation, triggering a favorable physiological and growth response to water stress. On the other hand, when Zarina was used as the scion (JosxZar), these grafted plants showed an increase in the photorespiration cycle, which may generate amino acids and proteins and could explain their better growth under stress conditions. In conclusion, grafting improves N uptake or photorespiration, and increases leaf NO3photoassimilation in water stress experiments in tomato plants. E. Sa´nchez-Rodrı´guez (&) L. Romero J. M. Ruiz Department of Plant Physiology, Faculty of Sciences, University of Granada, 18071 Granada, Spain e-mail: [email protected]
Keywords Ammonium assimilation Lycopersicon esculentum Mill Nitrate reduction GS/GOGAT cycle Photorespiration Grafting
Introduction Water is crucial for plant growth (Boyer 1982), and, as such, an increase in the prevalence of drought will have an important negative impact on the productivity of agriculture (Passioura 2007). In general, drought depresses nutrient uptake by the root and transport to the shoot due to a restricted transpiration rate affecting active transport and membrane permeability (Kramer and Boyer 1995). Drought-dependent nitrogen deficiency may contribute to growth limitation under water deprivation (Heckathorn and others 1997). Many researchers have shown a directly proportional relationship between nitrate (NO3-) and yield, and also between yield and foliar nitrogen (N) content (Kim and others 2011; Li and Lascano 2011). For this reason, crops that maintain a high N content and productivity under water stress are indispensable. Nitrate is the main nitrogen sour
Data Loading...
