Comparative Responses of Two Kentucky Bluegrass Cultivars to Salinity Stress

Abstract

Little information is available concerning physiological responses of Kentucky bluegrass (Poa pratensis L.) (KBG) cultivars to salinity. Growth and physiological responses of ‘Limousine’ and ‘Kenblue’ KBG to a range of salinity levels were investigated. Grasses were grown in solution culture and exposed to salinity levels of 2.2, 5.2, 8.2, 11.2, and 14.2 dS m−1 for 10 wk. Though both cultivars exhibited increased leaf firing with increasing salinity, Limousine exhibited less leaf firing than Kenblue at salinity levels above 5.2 dS m−1 In addition, salinity levels that caused 25% shoot growth reduction were 3.2 dS m−1 for Kenblue and 4.7 dS m−1 for Limousine, indicating that Limousine has better salinity tolerance. Under moderate (8.2 dS m−1) salinity stress, Limousine produced ∼50% more root growth than Kenblue. Water relations diverged between cultivars at 8.2 and 14.2 dS m−1, as Limousine had higher leaf water and osmotic potentials, as well as more positive turgor. While glycinebetaine was not detected in either cultivar, proline increased in leaves with increasing salinity, and was higher in Kenblue than Limousine at 8.2, 11.2, and 14.2 dS m−1 This suggests that compatible solute accumulation is not a salinity tolerance mechanism of KBG, and that proline accumulation is merely an indication of salt injury. Limousine maintained 52% lower shoot Na+, 30.4% lower Cl−, and 52% higher shoot K+/Na+ ratio than Kenblue at the highest salinity level. These results suggest that salinity tolerance in KBG is largely attributable to maintenance of higher root growth, and more positive turgor, higher K+/Na+ ratio, and less Cl− accumulation in shoots. These traits may serve as useful selection criteria in breeding efforts to develop salt tolerant KBG.

Physiological adaptative characteristics of Imperata cylindrica for salinity tolerance

“…Both populations showed more negative leaf osmotic potential and water potential with increasing salt levels, but the Salt Range population maintained its leaf water, osmotic and turgor potentials under saline conditions more efficiently, which may be an important strategy of this population to survive under physiological droughts caused by saline conditions. Qian et al (2001) reported similar findings in Kentucky bluegrass in which salttolerant lines maintained high turgor potential under unfavorable conditions.…”

“…It is widely accepted that halophytic or salt tolerant plants have a restricted uptake and low rate of transportation of toxic Na + and Cl − to the leaves and their compartmentalization within the cells to avoid salt toxicity (Munns 2002). This may be an important adaptation of the Salt Range population of this grass for thriving well under high salinities as reported by Qian et al (2001) in Kentucky bluegrass and Hameed & Ashraf (2008) in Cynodon dactylon.…”

Comparison of ionic concentration, organic solute accumulation and osmotic adaptation in Kentucky bluegrass and Tall fescue under NaCl stress

“…), a moderately salt-tolerant C 3 species with an EC threshold of 6-10 dS m À1 (Harivandi 1988), is becoming an increasingly important lawn species and is widely used as a utility turfgrass in both warm and cool subtropical areas (Turgeon 2008). Several studies have assessed the effects of high salinity on KBG and TF (Horst and Beadle 1984;Qian et al 2001;SuplickPloense et al 2002;Wipff and Rose-Fricker 2003). However, the contributions of specific inorganic ions and compatible solutes to osmotic potential under saline conditions are not clear.…”

“…However, osmotic adjustment of KBG and TF is not reported yet. Qian et al (2001) assayed two KBG cultivars for compatible solutes; they found proline at concentrations too low for osmotic adjustment, and no glycinebetaine. We hypothesized that the degree of salt tolerance of KBG and TF is related to ion regulation and sugar accumulation.…”

PRODUKSI, KUALITAS, DAN KECERNAAN IN VITRO TANAMAN RUMPUT BENGGALA (Panicum maximum) PADA LAHAN SALIN

“…Salinitas menurunkan laju pertumbuhan daun melalui pengurangan laju pembesaran sel pada daun. Penelitian Qian et al (2001) dan Amezketa et al (2005) menyatakan bahwa salinitas menyebabkan terhambatnya pertumbuhan tanaman dan perubahan struktur tanaman, antara lain lebih kecilnya ukuran daun, lebih rapatnya stomata, dan lignifikasi akar yang lebih awal.…”