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\hypersetup{pdftitle={Comparison of Ionic and Osmotic Stress of Salinity on Germination   and Seedling Growth of Agropyron Cristatum and Agropyron Elongatum },pdfauthor={Behzad Behtari, Farzaneh Gholami},pdfsubject={Tropentag 2010: Abstract},pdfkeywords={Agropyron elongatum and A. cristatum, osmotic and ionic effects, PEG 6000, salinity},pdfpagemode=None,colorlinks=true}
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\parbox[b]{13.4cm}{\centering \large{\textbf{Tropentag, September 14-16, 2010, Zurich}}\\[1ex] \Large{``World Food System  ---\\A Contribution from Europe''\\[2ex]}}
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\Large{\textbf{Comparison of Ionic and Osmotic Stress of Salinity on Germination   and Seedling Growth of Agropyron Cristatum and Agropyron Elongatum \footnote{\textbf{Contact Address:} Behzad Behtari, Tarbiat Modares University, Natural Resources, P.O. Box. 14115-111, Tehran, Iran, \mbox{e-mail}: \email{b.behtari@gmail.com}}\\[0.8ex]}}
\normalsize{\textsc{Behzad Behtari$^{1}$, Farzaneh Gholami$^{2}$}}
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\begin{itemize*}
\item[]{\small{\textit{$^{1}$Tarbiat Modares University, Natural Resources, Iran}}}
\item[]{\small{\textit{$^{2}$Tarbiat Modares University, Natural Resources, Iran}}}
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\index[author]{Behtari, Behzad}
\index[author]{Gholami, Farzaneh}
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\textbf{Abstract}
\begin{abstract}
\normalsize{
Wheatgrass (Agropyron) is one of important forage crops and used perennial cool"=season turf and forage grass species. Seeds of plants under natural conditions are subjected to salinity (usually NaCl) Salt and osmotic stresses are responsible for both inhabitation or delayed seed germination and seedling establishment. The aim of study was determine factor responsible for failure of germinations and growth of Agropyron cristatum and Agropyron elongatum seeds under saline conditions. Furthermore, were determining of inhibition of germination and growth due to an osmotic effect or due to the toxic effects of Na$^{+}$ and Cl$^{-}$ ions. In order to purpose, use the iso"=osmotic solutions of sodium chloride (NaCl) and Polyethylene glycol 6000 (PEG 6000) in osmotic stress levels (0, 4 and 8 bar) for induction of osmotic and ionic effects. Fifty seeds with four replications were placed on two layers of filter paper. Germination testes were conducted in a germinator maintained at 15---25\textdegree{}C during 16 hour light period and 8 hour dark. Germination percentage, speed of germination, shoot length and vigour index show decline significantly tendency between wheatgrasses. Only root length had no statically significant difference between stress levels 0 and 4 bar. iso"=osmotic solutions of NaCl and PEG 6000 in A. cristatum not showed statically significant difference but, in A. elongatum had statistically significant between iso- osmotic solution. This study showed that PEG 6000 for osmotic agent of salinity inhibition of germination and growth rather than ions effect of salt. However, increasing stress levels of medium to higher density, the effect is due to the toxicity effects. This study showed that tolerance of A. elongatum against salinity more than A. cristatum species. }

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\noindent \textbf{Keywords:} Agropyron elongatum and A. cristatum, osmotic and ionic effects, PEG 6000, salinity
\index[key]{Agropyron elongatum and A. cristatum}
\index[key]{Osmotic and ionic effects}
\index[key]{PEG 6000}
\index[key]{Salinity}
\end{document}