Changes in anatomy and root cell ultrastructure of soybean genotypes under manganese stress

Revista Brasileira de Ciência do Solo

José Lavres Junior²  Eurípedes Malavolta¹  Neusa De Lima Nogueira¹  Milton Ferreira Moraes¹  André Rodrigues Reis¹  Mônica Lanzoni Rossi¹  Cleusa Pereira Cabral² 

[1] ,Universidade de São Paulo Centro de Energia Nuclear na Agricultura Laboratório de Nutrição Mineral de PlantasPiracicaba SP

关键词: apoplast;    Glycine max;    optical microscopy;    root diameter;    apoplasto;    diâmetro radicular;    Glycine max;    microscopia óptica;   

DOI  :  10.1590/S0100-06832009000200017

来源: SciELO

【 摘 要 】

The deleterious effects of both Mn deficiency and excess on the development of plants have been evaluated with regard to aspects of shoot anatomy, ultrastructure and biochemistry, focusing mainly on the manifestation of visual symptoms. However, there is little information in the literature on changes in the root system in response to Mn supply. The objective of this study was to evaluate the effects of Mn doses (0.5, 2.0 and 200.0 μmol L-1) in a nutrient solution on the anatomy of leaves and roots of the Glycine max (L.) cultivars Santa Rosa, IAC-15 and IAC-Foscarin 31. Visual deficiency symptoms were first observed in Santa Rosa and IAC-15, which were also the only cultivars where Mn-toxicity symptoms were observed. Only in IAC-15, a high Mn supply led to root diameter thickening, but without alteration in cells of the bark, epidermis, exodermis and endodermis. The degree of disorganization of the xylem vessels, in particular the metaxylem, differed in the cultivars. Quantity and shape of the palisade parenchyma cells were influenced by both Mn deficiency and toxicity. A reduction in the number of chloroplasts was observed in the three Mn-deficient genotypes. The anatomical alterations in IAC-15 due to nutritional stress were greater, as expressed in extensive root cell cytoplasm disorganization and increased vacuolation at high Mn doses. The degree of changes in the anatomical and ultrastructural organization of roots and leaves of the soybean genotypes studied differed, suggesting the existence of tolerance mechanisms to different intensities of Mn deficiency or excess.

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