Effect Of Foliage Application Of Glycinebetaine On Heavy Metals Uptake By Edible Amaranth

Effected by the irrigation and fertilizer, lots of saline soil was contaminated by poisonous heavy metals. Under salinity-alkalinity and heavy metal pollution environment, the growth of crop would be influenced by salt ions and heavy metals, giving rise to osmotic stress. However, glycinebetaine which acted as the main organic osmoregulation substances in plants could improve the balance of osmotic adjustment. Consequently, the exogenously application of betaine was frequently used as a way of increasing resistance and promoting the growth of crops. As a result, a pot experiment was adopted with soil contaminated by complicated heavy metals, like cadmium and lead, and exogenously applied glycinebetaine(GB, 1mmol/L,5 mmol/L,10 mmol/L,20 mmol/L,50 mmol/L) during different stage of edible amaranth to study the effect of glycinebetaine on the uptake of heavy metals in non-saline and saline soil environment. Results showed that:(1) In non-saline soil environment, exogenous spraying glycinebetaine enhanced the content of dry matter, soluble sugar, free proline. Exogenous glycinebetaine reinforced the absorption of Ca, Mg, Fe, Na, and the absorption of Ca, Mg in the root kept rising with the increase of glycinebetaine. The application of glycinebetaine increased the absorption of Cd, Pb, Cu in the root, and the cumulant was more evident when sprayed at the stage of 30 th day.(2) In saline soil environment, spraying 50 mmol/L glycinebetaine significantly improved the concentration of free proline and total free amino acid in the shoot of edible amaranth. At the salinity of 0.4% and spraying 50 mmol/L glycinebetaine, the ratio of K and Na, Ca and Na was increased by 40.4% and 34.1% in the root, respectively. Exogenous glycinebetaine improved the absorption and accumulation of Cd, Cr, Pb, Cu and Zn by crop. At 0.4% salinity and 50 mmol/L glycinebetaine treatment, the concentration of Cd, Cr, Pb, Cu and Zn in root was promoted by 22.1%, 127.1%, 63.4%, 61.1% and 56.1%, respectively. Therefore, the application of glycinebetaine reinforced the resistance of salinity, so as the high accumulant of heavy metals.(3) In saline soil environment, salinity stress increased the concentration of Cd, Cr, Pb, and exogenous glycinebetaine further promoted the content of Cd, Pb, Cu markedly in the rhizosphere solution, especially in 50 mmol/L glycinebetaine. Exogenous glycinebetaine resulted in an increase in IAA, total pectin and chlorophyll effectively, and a decrease in MDA. Thus, exogenous glycinebetaine could increase total pectin, chlorophyll and its important component of Ca, Mg to prevent osmotic imbalance commonly, providing the possibility of entering into the plasma membrane for heavy metals with other essential ions indirectly.