Relationship between salt tolerance and photosynthetic machinery performance in citrus

• Published in: Environmental and experimental botany Vol. 62; no. 2; pp. 176 - 184
• Main Authors: López-Climent, María F., Arbona, Vicent, Pérez-Clemente, Rosa M., Gómez-Cadenas, Aurelio
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.03.2008; Elsevier Science
• Subjects: Adaptation to environment and cultivation conditions; Agronomy. Soil science and plant productions; bioaccumulation; Biological and medical sciences; chlorides; chlorophyll; Citrus; citrus fruits; crop yield; fluorescence; Fundamental and applied biological sciences. Psychology; Fv/Fm; Genetics and breeding of economic plants; genotype; leaves; NPQ; Photosynthesis; photosystem II; plant growth; Quantum yield; Salinity; salt stress; salt tolerance; species differences; Stomatal conductance; Varietal selection. Specialized plant breeding, plant breeding aims; Fv/Fm; Stomatal conductance; C i; Photosynthesis; Quantum yield; NPQ; Salinity; Ci; Rutaceae; Tolerance; Citrus; Dicotyledones; Angiospermae; Spermatophyta
• ISSN: 0098-8472; 1873-7307
• DOI: 10.1016/j.envexpbot.2007.08.002

In citrus, salt stress has been related to the build up of chloride ions in plant tissues that affect photosynthesis, growth and yield. We investigated the effects of salt stress on the stability of the photosynthetic machinery with respect to the relative salt tolerance of different citrus genotypes including: Swingle Citrumelo, Carrizo citrange, C35 citrange, Cleopatra mandarin and Forner-Alcaide #5. Under identical salt-stress conditions, Forner-Alcaide #5 and Cleopatra mandarin accumulated less chloride ions in leaves than the other genotypes and showed a better plant performance. Chlorophyll fluorescence parameters indicated severe impairments of photosynthetic activity in salt-sensitive Citrumelo and citranges but Cleopatra and Forner-Alcaide #5 were less affected. In addition, differences in photosynthetic responses between these two moderately tolerant genotypes suggested different strategies to cope with salinity. The high tolerance to salinity shown by Forner-Alcaide #5 can be associated to the ability of keeping an active photosynthetic system at elevated saline conditions whereas the tolerance of Cleopatra was linked to rapid reductions of net photosynthetic rate, stomatal conductance, performance of PSII and photosynthetic efficiency.