Large genetic variability has been observed in rice (Oryza sativa L). for different root traits such as root depth, root thickness and root-to-shoot ratio (O'Toole and Bland, 1987).
In parallel with genetics approaches, efforts have been made to screen mutant libraries for lines presenting alterations in root development, allowing for the identification of several genes that control different steps of root development, such as crown root and lateral root initiation and emergence, meristem patterning, and the control of root growth.
The expression profile of MT2-1 genes in different organs, such as root, stem, and leaf, has been studied in several plant species.
Previously, a macro array that contained a total of 1,786-unigene 1,786-unigenefrom a common bean nodule cDNA library wasetsederivedranscript profromng of different organs sucommonroot, leaf, stem, and pod [ 6].
Besides, the effects were different in different seedling parameters such as germination, root length, shoot length and their ratios.
RT-PCR experiments were performed to assess the occurrence of RE transcripts in different organs such as root, leaf, flower (at three different stages) and embryo (at four different stages), collected from HCM line plants.
An analysis of the structural-functional organization of cells in different root cap layers of such higher plants as pea, Arabidopsis thaliana, and Brassica rapa grown under 1 g, on the clinostats, and in microgravity, allows us to support the hypothesis that amyloplasts function as statoliths in statocytes, but they may not be only the passive statolithic mass.
To date gene expression studies in maize in response to water stress have investigated different organs such as roots [23] and developing kernels [24] or particular developmental stages [25].
Comparing defense traits in different tissues, such as roots, of N. attenuata plants grown in single pots with plants in competition will help to answer these questions.
Root characteristics such as root length density and root weight density have been identified as important factors because N uptake is determined by root mass and N uptake per unit root volume (Shimono and Bunce 2009).
