Salicylic acid and nitric oxide alleviate osmotic stress in wheat (Triticum aestivum L.) seedlings

 To investigate the responses of growth and antioxidant enzymes to osmotic stress in two different wheat cultivars, one drought tolerant (Heshangtou, HST) and the other drought sensitive (Longchun 15, LC15), 15-day-old wheat seedlings were exposed to osmotic stress of –0.25, –0.50, and –0.75 MPa for 2 days. It is found that osmotic stress decreased shoot length in both wheat cultivars, whereas to a lesser degree in HST than in LC15. The contents of malondialdehyde (MDA) and the activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) of shoot in both wheat cultivars were increased by osmotic stress. It is clear that MDA contents increased less in the more drought tolerant cultivar HST than in drought sensitive one LC15. On the contrary, POD and CAT activities increased more in HST than LC15 under osmotic stress. As the activity of SOD, however, no significant differences were found between HST and LC15. These results suggest that wheat cultivar HST has higher activities of antioxidant enzymes such as POD and CAT to cope with oxidative damage caused by osmotic stress compared to sensitive LC15.  

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The Effect of Salicylic Acid on Resistance in Wheat (Triticum aestivum) Seedling Roots Against the Take-All Fungus, Gaeumannomyces graminis var tritici

Australian Journal of Botany ◽

10.1071/bt9960499 ◽

1996 ◽

Vol 44 (4) ◽

pp. 499 ◽

Cited By ~ 9

Author(s):

S Seah ◽

K Sivasithamparam ◽

DW Turner

Keyword(s):

Triticum Aestivum ◽

Salicylic Acid ◽

Wheat Seedling ◽

Triticum Aestivum L ◽

Gaeumannomyces Graminis ◽

Resistance Response ◽

Wheat Seedlings ◽

Seedling Roots ◽

Wheat Seedling Roots ◽

Take All

The effect of salicylic acid (SA) applied as foliar dip, foliar wipe, root drench or pre-germination soak on the susceptibility of wheat (Triticum aestivum L.) seedlings to Gaeumannomyces graminis (Sacc.) Arx & Olivier var. tritici Walker (take-all fungus, Ggt) was studied. It was hypothesised that an increase in SA concentration applied using these methods would increase the resistance in wheat seedling roots against Ggt. Leaves (by foliar wipe and foliar dip) and roots (by root drench) of 1-2-week-old wheat seedlings grown in Lancelin sand, were treated with 0, 0.1 or 1 mM SA, and treatments of 0, 0.1 or 0.5 mM SA were applied in a pre-germination soak method. Ggt infection reduced (P Ͱ4 0.05) chlorophyll content and concentration and root length (P Ͱ4 0.10). Experiments that were conducted suggested that the SA treatments failed to induce a resistance response because they did not stimulate phenylalanine ammonia-lyase and peroxidase activities in the wheat seedling roots. Therefore, SA applied using these methods was not effective in reducing the susceptibility of wheat seedlings to Ggt. The chemical or biological induction of resistance in plant roots and its applicability as a root disease control strategy requires further clarification.

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