International Journal of Botany1811-97001811-9719Asian Network for Scientific Information10.3923/ijb.2007.78.84MusyimiD. M.NetondoG. W.OumaG. 1200731This study was conducted to investigate growth and gas exchange characteristics of avocado seedlings growing under different salinity levels under naturally illuminated greenhouse conditions, in order to relate this physiological information to the ecology of this avocado cultivar. Plants grown in 4.5 L plastic pots containing soil were subjected to 0 (control), 15, 30, 45 and 60 mM NaCl salinity treatments. The measured parameters started to show significant differences (p≤0.05) by day 7. Interactions between salt treatments and duration of salt exposure were highly significant at p≤0.05. Net photosynthetic rate (PN), stomatal conductance (gs), transpiration rate (E) and chlorophyll (chl) concentration decreased in response to increasing salt concentration in the growth medium. Water use efficiency (WUE) decreased in all the treatments during the time course of experiment. Substomatal CO2 concentration (Ci) and chloride ions content increased with increasing salt concentration of the growth medium. It is suggested that the greater inhibition of CO2 fixation may be due to impairment of photosynthetic apparatus. Treatment consisting of 60 mM NaCl caused maximum growth reductions. The findings in this study demonstrate that NaCl salinity hampers growth and gas exchange processes of avocado plants and improvement in salt resistance of avocado rootstock under study is more likely to come from increasing further screening of more avocado rootstocks for salt tolerance or resistance.]]>Arnon, D.I.,1949Beta vulgaris.]]>24115Ashraf, M., F. Karim and E. Rasul,20023) and salt stress on growth, ion accumulation and photosynthetic capacity of two-spring wheat (Triticum aestivum L.) cultivars differing in Salt tolerance.]]>364959Bar, Y., A. Apelbaum, U. Kafkafi and R. Goren,1996Citrus plants: Alleviation of stress by nitrate supplementation via irrigation water.]]>121507513 Belkhodja, R., F. Morales, A. Abadia, H. Medrano and J. Abadia,1999Hordeum vulgare L.) grown under a triple-line-source sprinkler system in the field.]]>34375387Boyer, J.S.,197148532534Bradford, K.J.,198373475479Bradford, K.J.,198373480483Branson, R.L. and C.D. Gustafson,1972555660Cramer, G.R., G.J. Alberico and C. Schmidt,199421663674Crowley, D.E. and W. Smith,19991999Farquhar, G.D. and T.D. Sharkey,198233317345Flowers, T.J., F.M. Salama and A.R. Yeo,1988Oryza sativa L.) in relation to resistance to salinity.]]>11453459Gorrham, J., R.G. Wyn Jones and E. McDonnel,1985894156Hand, J.M., E. Young and A.C. Vasconcelos,19826910511054Hasegawa, P.M., R.A. Bressan, J.K. Zhu and H.J. Bohnert,200051463499Hofshi, R.,199579185197Hofshi, R.,199882137154Jimenez, M.S., A.M. Gonzalez-Rodriguez, D. Morales, M.C. Cid, A.R. Socorro and M. Caballero,199733291301Lutts, S., J.M. Kinet and J. Bouharmont,1996Oryza sativa L.) cultivars differing in salinity resistance.]]>78389398Marler, T.E. and Y. Zozer,1996Annona squamosa L.]]>121243248Mickelbart, M.V. and M.L. Arpaia,2002Hass avocado trees in response to salinity.]]>127649655Munns, R. and A. Termaat,198613143160Munns, R.,200225239250Netondo, G.W., J.C. Onyango and E. Beck,200444797805Netondo, G.W., J.C. Onyango and E. Beck,200444806811Oster, J.D. and M.L. Arpaia,19921992pp: 209214Rao, M., R.E. Sharp and J.S. Boyer,19878412141219Reinhardt, D.H. and T.L. Rost,1995108403465Richardson, S.G. and K.J. McCree,19857910151020Robertson, J.M., R.P. Pharis, Y.Y. Huang, D.M. Reid and E.C. Yeung,19857910861089Robinson, S.P.,1985799961002Robinson, S.P., W.J.S. Downton and J.A. Millhouse,198373238242Schaffer, B. and A.W. Whiley,20032003pp: 335342Seeman, J.R. and T.D. Sharkey, 1986Phaseolus vulgaris L.]]>82555560Shalhevet, J.,19991999pp: 8491Sharp, R.E. and J.S. Boyer,1986829095Sibole, I.V., C. Cabot, C. Poschenrieder and J. Barcelo,20035421112119Soussi, M., A. Ocana and C. Lluch,1998Cicer arietinum L.).]]>4913291337Turner, N.C.,198613175190USDA,1992pp: 294pp: 294