Effects of salinity and rootstock on growth, water relations, nutrition and gas exchange of loquat

SummaryPotted plants of loquat (Eriobotrya japonica Lindl.) cv. ‘Algerie’ grafted onto anger (Cydonia oblonga Mill.) or onto loquat were given 25, 35, 50 or 70 mM NaCl for 5 months. Total plant dry weight (DW) of loquat grafted onto anger was unaffected by salinity, whereas DW declined in plants grafted onto loquat. This decline was due mainly to lower leaf DW, with a smaller effect on roots and stems. Plants grafted onto anger had lower NA concentrations in their leaves than those grafted onto loquat at all salinities tested, and lower concentrations of Cl at the highest salinity, suggesting some resistance to the movement of ions from roots to shoots and/or lower Na and Cl uptake. The accumulation of salts in the leaves was associated with osmotic adjustment in both groups of plants. This osmotic adjustment maintained predawn and midday leaf turgor in plants grafted onto anger, but less so in plants grafted onto loquat. Leaf gas exchange declined in both groups of plants, despite the maintenance of cell...