Subcellular distribution and chemical forms of cadmium in Morus alba L.

Morus alba L. (mulberry) is a perennial woody tree and a species with great potential for Cd phyremediation owing to its large biomass and extensive root system. The mechanisms involved in Cd detoxification were investigated by analyzing the subcellular distribution and chemical forms of Cd in mulberry in the present study. These results indicated that 53.27-70.17% of Cd mulberry accumulated was stored in the root and only about 10% were in the leaves. Lots of the Cd was located in the cell wall of the mulberry root and in soluble fraction of the mulberry leaf. Moreover, in roots, the largest amount of Cd was in the form of undissolved Cd-phosphate. While in mulberry leaves and stems, most of the Cd was extracted by 2% Acetic acid and 0.6 M HCl, representing Cd-phosphate and Cd-oxalate. It could be concluded that the Cd combination with peptides and organo-ligands in vacuole of leaf or complexed with proteins or cellulose in the cell wall of root might be contributed to the tolerance of mulberry to Cd stress. The mulberry could be used to remediate the Cd polluted farmland soils.

Variations in the levels of mulberroside A, oxyresveratrol, and resveratrol in mulberries in different seasons and during growth.

This study aimed to investigate the composition of three major stilbenes (mulberroside A, oxyresveratrol, and resveratrol) in different portions of mulberries collected in different seasons and their change molds during growth by high-performance liquid chromatography. Mulberroside A levels were the highest in the bark and roots of Morus atropurpurea Roxb, Morus alba Linn, and Morus latifolia Poir. Oxyresveratrol levels were the highest in roots and stem. Both of these high levels were in September. The amount of resveratrol was very low in all samples. In the stem, Morus latifolia Poir contained more mulberroside A than the other two mulberries. Mulberroside A was not detected in the leaves of the three mulberries. In Morus atropurpurea Roxb seedlings, the root tended to contain more of the three stilbenes than leaves. The temporal peaks of resveratrol were always ahead of those for oxyresveratrol. The levels of the stilbenes varied in different portions of the varieties of mulberries collected in different season and in the seedlings of Morus atropurpurea Roxb.

[Comparative and correlational studies on contents of stilbenes in different portions of mulberry].

OBJECTIVE: To compare the contents of stilbenes in different parts and axial root bark of mulberry, and study their correlation. METHOD: The contents of 3 major stilbenes, mulberroside A, oxyresveratrol, and resveratrol in different parts of mulberry were determined by HPLC. The correlation and regression analysis between the contents of stilbenes in the different parts and axial root bark was carried out. RESULT: The contents of stilbenes in most different parts of mulberry showed significant correlation. Between the contents of stilbenes in the different parts and axial root bark, oxyresveratrol showed significant correlation among all different parts, resveratrol showed significant correlation except in spinal cord of annual branch, mulberroside A showed significant correlation between bark of annual branch, lateral root and axial root bark. The results of the correlation and regression analysis indicated that the contents of mulberroside A, oxyresveratrol, resveratrol in different parts and axial root bark were significant positively correlated. CONCLUSION: The contents of stilbenes are significant correlation distributed in different parts and axial root bark of mulberry. The contents of stilbenes in different parts could be used to estimate the content of the axial root bark. The result could be useful for breeding and preserving excellent germplasm at the system breed process for mulberry of rich in stilbenes.