Exogenously applied antioxidants and biostimulants alleviate salt stress in sweet pepper
2012
Sakr, M.T. | El-Sarkassy, N.M. | Fuller, M.P.
Saline soils are responsible for the restriction in yield of many crop plants and/or the limitation of marketable yield of several vegetable fruit crops such as sweet pepper. Whilst genetic solutions to these problems are being sought, exogenously applied ameliorants are needed to reduce the effects of salt. Experiments were carried out during the two growing seasons 2007 and 2008 to investigate the effect of salinity stress on growth, yield and endogenous bio-constituents and to examine whether salinity stress can be offset by the exogenous application of some antioxidant materials on sweet pepper (Capsicum annuum L. cv. Orlando). Salinity stress (2, 4 or 6 g L. -1) ,decreased growth at 75 days after transplanting and marketable yield. Applied antioxidants and bio-stimulants counteracted the harmful effects of low and moderate salinity stress levels (2 and 4 g L. -1) and partially couteracted the harmful effects under the highest salinity stress level (6 g L . 1). Ascorbic acid and sea weed extract (SWE) were the most effective agents in this respect Salinity stress levels increased super oxide dismutase (SOD), ascorbic peroxidase (APX) activity, proline content, and Na content but decreased photosynthetic pigment in the leaves and K in shoot of pepper plants. In addition, all of the applied antioxidants alone or combined with different salinity stress levels slightly increased the content of ascorbic acid and glutathione and the activity of SOD, APX. These results provide support for the field application of bio-stimulants and antioxidant compounds to alleviate the symptoms and effects of salty soils.
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