Linking diverse salinity responses of 14 almond rootstocks with physiological, biochemical, and genetic determinants

Abstract

Fourteen commercial almond rootstocks were tested under five types of irrigation waters to understand the genetic, physiological, and biochemical bases of salt-tolerance mechanisms. Treatments included control (T1) and four saline water treatments dominant in sodium-sulfate (T2), sodium-chloride (T3), sodium-chloride/sulfate (T4), and calcium/magnesium-chloride/sulfate (T5). T3 caused the highest reduction in survival rate and trunk diameter, followed by T4 and T2, indicating that Na and, to a lesser extent, Cl were the most toxic ions to almond rootstocks. Peach hybrid (Empyrean 1) and peach-almond hybrids (Cornerstone, Bright’s Hybrid 5, and BB 106) were the most tolerant to salinity. Rootstock’s performance under salinity correlated highly with its leaf Na and Cl concentrations, indicating that Na+ and Cl- exclusion is crucial for salinity tolerance in Prunus. Photosynthetic rate correlated with trunk diameter and proline leaf ratio (T3/T1) significantly correlated with the exclusion of Na+ and Cl-, which directly affected the survival rate. Expression analyses of 23 genes involved in salinity stress revealed that the expression differences among genotypes were closely associated with their performance under salinity. Our genetic, molecular, and biochemical analyses allowed us to characterize rootstocks based on component traits of the salt-tolerance mechanisms, which may facilitate the development of highly salt-tolerant rootstocks.

Linking Genetic Determinants With Salinity Tolerance and Ion Relationships in Eggplant, Tomato, and Pepper

“…Previous research suggests that the ability of a plant to manage Na, Cl, and K during salinity stress is critical for its ability to tolerate salinity 24,25,40 . After evaluating these cultivars under the hot eld climatic conditions of southern California for their whole cycle, it is reasonable to assume that, for the cultivars reported here as salt-sensitive, salt effects were related to ion toxicity rather than osmotic stress.…”

“…As Na + competes with K + for binding sites, high salt negatively affects the K content in plants 47 . Most plants show decreased leaf K concentration under salinity 40,48 ; this includes tomato 16,49−51 , where yield loss in NaCl solution was attributed to Na induced K de ciency 52 . However, in tomato studies with multiple salinity levels, leaf K levels did not signi cantly decrease until large yield losses occurred 12,24 .…”

“…In almond, a study focusing on characterizing salinity responses in 14 almond rootstocks, the percent reduction in leaf K concentration under salinity was highly correlated with salinity tolerance 40 .…”

“…It has been observed in some plant species that the basic expression levels of several genes involved in salinity stress are higher in salt-tolerant genotypes compared to salt-sensitive genotypes 40 . Based on the genes tested in this investigation, we did not see that general trend (Fig.…”

Morphological, Physiological, Biochemical, and Transcriptome Studies Reveal The Importance of Different Component Traits During Salinity Stress in Prunus

“…The effect of excess salts also depends on the ionic composition of waters, not just the total salinity. When compared to 5 different saline water treatments, almond rootstocks grown under sodium/chloride-dominant waters had the highest reduction in survival rate and trunk diameter 21 .…”