In vitro olive (Olea europaeaL.) cvs Frantoio and Moraiolo microshoot tolerance to NaCl

Abstract

In vitro culture of rooted and unrooted olive microshoots, established from seed lines of free-pollinated ''Frantoio'' and ''Moraiolo'' cultivars, were evaluated for NaCl tolerance. The aim was to use growth and physiological parameters in order to identify salt-adapted genotypes. Leaf tissue elemental distribution of Na, Cl and K was also investigated in unrooted plantlets by cryo-scanning electron microscopy and energy-dispersive X-ray microanalysis. Both in unrooted and rooted plantlets, increased concentrations of NaCl reduced shoot growth, whereas plant survival was not affected. However, no significant interactions between line and NaCl concentration were found. Elemental distribution showed that Moraiolo J and Frantoio Z accumulated more Na and Cl inside leaves, and that these elements followed a tissue-dependent pattern. Rooting capacity was reduced at the higher levels of NaCl. Significant interactions between seed line and salt treatment were found. Seed lines showed different abilities to develop roots at different salt levels. In particular, Frantoio Z showed a significant and different behaviour relative to the other seed lines at 50 mM NaCl with regard to both length and dry weight of roots. The results obtained suggest that rooting parameters are the most useful tools in the evaluation and screening of salt-tolerant olive genotypes through in vitro shoot culture.

Effects of optimal and supra-optimal salinity stress on antioxidative defence, osmolytes and in vitro growth responses in Sesuvium portulacastrum L.

“…In addition, the ultrastructural changes at the nuclear and cytoplasm level (Bennici and Corrado 2009) in different parts of the axillary shoots due to toxic concentrations of salt might have contributed to reduced growth. As in our study, the sodium concentration was more than 10 mmol g -1 DW; the response of growth reduction might be specifically attributed to the toxic concentration of sodium ions rather than the nutritional disturbance, which is in agreement with Vicente et al (2004) and Bracci et al (2008). The accumulation of sodium and concomitant decrease in potassium levels appear to be one of the general characteristics of halophytes.…”

“…The possibility and the advantages of using in vitro shoot cultures to evaluate salt tolerance have been reported in many plants such as tomato (Cano et al 1998), rice (Basu et al 2002), mulberry (Vijayan et al 2003), Plantago crassifolia (Vicente et al 2004) and Olea europaea (Bracci et al 2008). Most of these investigators indicated shoot cultures as the best choice for physiological studies because many of the plant responses to salt stress are due to an integrated functioning of shoots and roots in toxic ions exclusion or inclusion that cannot be evidenced in callus and cell cultures (Vijayan et al 2003).…”

“…Besides, in vitro studies allow relatively faster responses, shorter generation time and controlled environment as compared to ex vitro conditions (Zhang et al 2004;Pérez-Tornero et al 2009) and the inferences obtained from in vitro cultures under salt stress may be directly applicable at the whole-plant level. Several studies have shown that in vitro culture is a reliable method for testing salt tolerance in many plants using both shoot apex and callus cultures (Cano et al 1998;Basu et al 2002;Bracci et al 2008). Shoots in comparison to callus cultures are easy to propagate in vitro and plant material selected from salt-stressed cultures can be used to establish plantation in saline soils.…”

Understanding olive adaptation to abiotic stresses as a tool to increase crop performance

“…Reductions in growth and yield due to salinity have been widely reported Chartzolulakis et al, 2002;Chartzoulakis 2005;Bracci et al, 2008). Longterm studies with trees under field conditions by Aragües et al (2005) with 'Arbequina' trees show that above 4 dS m -1 EC, reductions in yield ranging from 16 to 23% per 1 dS m -1 occurred.…”

Influence of salinity on root hydraulic properties of three olive varieties

“…Furthermore, although the root system is the first plant organ to be affected by salt stress, and root traits are thought to be among the most useful tools in evaluating and screening of salt tolerance (e.g. for olive see Bracci et al 2008), most studies have focussed on above-ground organs (e.g. Demiral 2005;Junghans et al 2006).…”