Promotion of 5‐aminolevulinic acid on photosynthesis of melon (Cucumis melo) seedlings under low light and chilling stress conditions

Abstract

When melon seedlings (Cucumis melo L. Ximiya No. 1) were cultured in a growth chamber with about 150 micro mol m(-2) s(-1) photon flux density, the leaf photosynthetic ability reduced dramatically as leaf position decreased from the top. The application of 5-aminolevulinic acid (ALA) solutions significantly increased the net photosynthetic rate (P(n)) as well as apparent quantum yield (AQY), carboxylation efficiency (CE) and stomata conductance (G(s)). After irrigation with 10 ml of ALA solution (10 mg l(-1) or 100 mg l(-1)) per container filled with approximately 250 g clean sand for 3 days, the leaf P(n) was about 40-200% higher than that of controls, and AQY, CE and G(s) increased 21-271%, 55-210% and 60-335%, respectively. Furthermore, ALA treatments increased leaf chlorophyll content and soluble sugar levels, as well as the rate of dark respiration, but decreased the rate of respiration under light. On the other hand, after melon seedlings that had been cultured in the chamber suffered chilling at 8 degrees C for 4 h and then recovered at 25-30 degrees C for 2 and 20 h, the P(n) of the water-irrigated plants was only 12-18% and 37-47%, respectively, compared with the initial P(n) before chilling treatment. If the seedlings underwent the same treatment but with ALA (10 mg l(-1)), the respective P(n) was 22-38% and 76-101%, compared with that of the control before chilling stress. If chilling was prolonged for 6 h, the ALA-pre-treated plants only showed a few symptoms in the leaf margins whereas all water-irrigated plants died, which suggested that ALA presumably promoted chilling tolerance of the plants under low light.

Influence of Precursors and Inhibitor on the Production of Extracellular 5-Aminolevulinic Acid and Biomass byRhodopseudomonas palustrisKG31

“…Biomass of photosynthetic bacteria has been used as a source of protein with high amounts of essential amino acids e.g., methionine and lysine, 5,6) and also as a feed supplement for producing low-cholesterol chicken eggs. 7) ALA can be applied as a plant growth-regulator and as a weed growth inhibitor, 1) in which a concentration range of 0.06-0.6 mM demonstrated plant regulating activities 8) whereas 4 mM ALA could be used to control weed (Trifolium repens) growth. 9) Application of ALA to date palm revealed that the fruit chlorophyll content at the Khalal stage was significantly increased.…”

“…It should be emphasized that the ALA content obtained in this study was enough to be used to promote plant growth. 8) The growth of the bacterium under the optimal conditions is shown in Fig. 2b.…”

Effect of 5-Aminolevulinic Acid (ALA) on Leaf Diurnal Photosynthetic Characteristics and Antioxidant Activity in Pear (Pyrus Pyrifolia Nakai)

“…This means that ALA treatment did not only promote stomatal opening, but also affect the non-stomatal factors related with photosynthesis (Farquhar and Sharkey, 1982). In other studies, exogenous ALA promotion on stomatal opening has been reported in melon (Wang et al, 2004a) or watermelon . A transgenic tobacco, which could over-produce endogenous ALA, also possessed higher stomatal conductivity (Zhang et al, 2010).…”

Application of 5-aminolevulinic Acid for the in vitro Micropropagation of Cymbidium as a Potential Novel Plant Regulator

“…Xu et al (2010) suggested that ALA at low concentrations could increase the growth of kudzu Pueraria phaseoloides) by increasing photosynthetic rate. Previous studies have shown that low concentrations of exogenous ALA promote plant growth, development, and responses to environmental stresses (Bindu and Vivekanandan, 1998), such as crop productivity (Hotta et al, 1997a) and stress tolerance (Hotta et al, 1998;Watanabe et al, 2000;Wang et al, 2004;Sun et al, 2009;Liu et al, 2011;Naeem et al, 2011). These previous studies suggest that the effect of ALA on plants depends on the concentration of ALA. ALA at low concentrations is known to promote growth and development of some plants, animals, algae and photosynthetic bacteria (Chakraborty and Tripathy, 1990;Balestrasse et al, 2010).…”

“…Exogenous ALA can enhance the quality of some medicinal plants (Xu et al, 2010;Xu and Cheng, 2011) and enhance the photosynthetic rate, chlorophyll content, and yield of lettuce (Xu et al, 2012). ALA has been proposed as a novel natural and environmentally friendly regulator that is widely used in agriculture (Wang et al, 2004). This compound appears to act as a hormonelike plant growth regulator and is effective at relatively low concentrations (Xu et al, 2010).…”