Effect of salinity stress on growth and carbohydrate metabolism in three Rice (Oryza sativa L.) cultivars differing in salinity tolerance

Applied Taxonomic Research Center, Department of Biology Faculty of Science, Khon Kaen University, Khon Kaen, 40002 Thailand.
Indian journal of experimental biology (Impact Factor: 0.75). 11/2008; 46(10):736-42.
Source: PubMed

ABSTRACT Rice seedlings cv. Khao Dawk Mali 105 (salt-sensitive), Luang Anan (moderately salt-tolerant) and Pokkali (salt-tolerant) were exposed to 0, 50, 100 and 150 mM NaCI for 9 d. Salinity stress caused reduction in leaf relative water contents in all cultivars. Shoot length of cv. Pokkali was least affected by salinity stress whereas increased root length in response to salinity stress was apparent in cvs. Khao Dawk Mali 105 and Luang Anan. Increased salinity level also caused reduction in fresh and dry weights in cvs. Khao Dawk Mali 105 and Luang Anan, but had no effect in cv. Pokkali except at 150 mM. Accumulation of total soluble sugars and sucrose in mature leaves were observed in cv. Khao Dawk Mali 105 exposed to high level of salinity whereas their concentrations in cvs. Luang Anan and Pokkali remained the same as control plants. Accumulation of sucrose in cv. Khao Dawk Mali 105 was suggested to be resulted from the alteration of photosynthate partitioning since the activities of sucrose phosphate synthase were not affected by salinity in this cultivar. On the contrary, salinity stress induced an accumulation of starch in cv. Pokkali. It is suggested that partitioning sugars into starch may involve in salinity tolerance by avoiding metabolic alterations.

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Available from: Maysaya Thitisaksakul, Jan 15, 2014
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    • "Similar conclusions were recorded by Khajeh-Hosseini et al. (2003), Jamil et al. (2006), Munns et al. (2006), Maghsoudi Moud and Maghsoudi (2008) and McGrath and Reyes (2008). Pattanagule and Thitisaksakul (2008) reported that carbohydrates are accumulated in plant tissues under saline condition and these substances are suspected of contributing to osmotic adjustment. Khavari- Nejad et al. (2008), Hajiboland et al. (2009), Dadkhah (2010) and Saadat et al. (2012) indicated that germination characters i.e. germination percentage and SVI were decreased as salinity concentration increased. "
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    • "Soluble sugars, the primary product of photosynthesis in higher plants, play a key role as building blocks of macromolecules controlling plant growth and development (Gibson 2000; Smeekens 2000; Price et al. 2004). They are not only involved in osmoregulation mechanisms within the cell, controlling water potential and osmotic potential (Pattanagul and Thitisaksakul 2008; Cha-um et al. 2009a, b), but also help in detoxification by acting as chelating agents to trap Na + within starch granules (Kanai et al. 2007). Interestingly, soluble sugars act as signal molecules and are also involved in regulating genes related to salt-tolerance defence mechanisms (Arbona et al. 2005; Gupta and Kaur 2005). "
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