5-Aminolevulinic acid improves photosynthetic gas exchange capacity and ion uptake under salinity stress in oilseed rape (Brassica napus L.)

Abstract

Salinity is one of the major constraints in oilseed rape (Brassica napus L.) production. One of the means to overcome this constraint is the use of plant growth regulators to induce plant tolerance. To study the plant response to salinity in combination with a growth regulator, 5-aminolevulinic acid (ALA), oilseed rape plants were grown hydroponically in greenhouse conditions under three levels of salinity (0, 100, and 200 mM NaCl) and foliar application of ALA (30 mg/l). Salinity depressed the growth of shoots and roots, and decreased leaf water potential and chlorophyll concentration. Addition of ALA partially improved the growth of shoots and roots, and increased the leaf chlorophyll concentrations of stressed plants. Foliar application of ALA also maintained leaf water potential of plants growing in 100 mM salinity at the same level as that of the control plants, and there was also an improvement in the water relations of ALA-treated plants growing in 200 mM. Net photosynthetic rate and gas exchange parameters were also reduced significantly with increasing salinity; these effects were partially reversed upon foliar application with ALA. Sodium accumulation increased with increasing NaCl concentration which induced a complex response in the macro-and micronutrients uptake and accumulation in both roots and leaves. Generally, analyses of macro-(N, P, K, S, Ca, and Mg) and micronutrients (Mn, Zn, Fe, and Cu) showed no increased accumulation of these ions in the leaves and roots (on dry weight basis) under increasing salinity except for zinc (Zn). Foliar application of ALA enhanced the concentrations of all nutrients other than Mn and Cu. These results suggest that under short-term salinity-induced stress (10 days), exogenous application of ALA helped the plants improve growth, photosynthetic gas exchange capacity, water potential, chlorophyll content, and mineral nutrition by manipulating the uptake of Na + .

Effects of exogenous 5-aminolevulinic acid on photosynthesis, stomatal conductance, transpiration rate, and PIP gene expression of tomato seedlings subject to salinity stress

“…1' plants. The same results have been observed in oilseed rape (Naeem et al, 2010). Previous research has also demonstrated the ability to improve g s and E of watermelon and pakchoi plants under different conditions by exogenous ALA treatment (Sun et al, 2009;Memon et al, 2009).…”

“…Watanabe et al (2000) evaluated12 different PGRs and found ALA to be the most effective in improving the salt tolerance of cotton. Thus far, research conducted on ALA has mainly focused on photosynthesis (Liu et al, 2013), chlorophyll accumulation (Memon et al, 2009), the antioxidant system (Nishihara et al, 2003;Sun et al, 2009), and ion uptake (Naeem et al, 2010). Although ALA has been reported to be capable of enhancing the salt tolerance of various plants, data on the molecular mechanism of exogenous ALA application are limited.…”

“…Although ALA has been reported to be capable of enhancing the salt tolerance of various plants, data on the molecular mechanism of exogenous ALA application are limited. Naeem et al (2010) reported that spraying ALA on oilseed rape improved leaf water relations under salinity stress. Our previous research found that ALA could regulate the transcription of aquaporins in cucumber leaves and enhance the salt tolerance of the plants (Yan et al, 2014).…”

Promotive effects of 5-Aminolevulinic acid on growth, photosynthetic gas exchange, chlorophyll, and antioxidative enzymes under salinity stress in Prunnus persica (L.) Batseh Seedling

“…NaCl tolerance is enhanced by increasing the osmolyte content and the physiological activity of protective enzyme systems in plants (Al-Qurashi et al, 2011). Exogenous ALA can improve protective enzyme activity and leaf photosynthesis in various crops, such as Cucumis sativus L. (Zhen et al, 2012), Solanum lycopersicum , Helianthus annuus L. (Akram et al, 2012), Brassica campestris L. (Naeem et al, 2010), Brassica rapa L. (Wang et al, 2005), Solanum tuberosum (Zhang et al, 2006), Oryza sativa L. (Nunkaew et al, 2014), and Creeping bentgrass (Yang et al, 2014), under salinity stress. As a result, the development and production of crops are facilitated, in addition, the inhibitory actions of salinity stress on plants are alleviated.…”

Effects of exogenous 5-aminolevulinic acid on PIP1 and NIP aquaporin gene expression in seedlings of cucumber cultivars subjected to salinity stress

“…Application of low concentration of exogenous ALA is known to promote plant growth development and response to environment stresses (Naeem et al, 2012), for example, enhancing salt tolerance in potato (Zhang et al, 2006) and chilling tolerance in pepper seedlings (Korkmaz et al, 2010). Foliar application of ALA can also improve leaf water relations in oilseed rape (Naeem et al, 2010). Na + concentration of cotton seedlings under salt stress were suppressed to low concentrations with ALA (Watanabe et al, 2000a).…”