Of 148 F2 seedlings, 43 seedlings showed Al resistance (RRE > 65%%) and short root phenotype in the absence of Al (Fig. 6a), whereas the remaining 105 seedlings with normal root elongation were intolerant to Al (RRE ≤ 65%%).
The poor root formation of the overexpression lines may be to ectopic expression of GSQUA2 under the 35S promoter, which interferes with the normal root development and is thus not necessarily informative of the gene's normal function.
When the normal roots are flooded and lose contact with the atmosphere, they commonly die due to the anoxic conditions that prevail in flooded soil (Ponnamperuma 1984).
Normal roots (not cluster roots) were used for RNA extractions and protein analysis.
The establishment of hairy root culture with highly increased levels of tricaffeoylquinic acids and their derivatives observed in the present study indicates that the hairy roots can be used as potential sources of these secondary metabolites instead of the normal roots of soil-grown plants.
Four kinds of tissue (normal shoot, normal root, shoot with 1-h stressty stress, or root with 1-h stressty stress) were collected and immediately frozen in liquid nitrogen.
Similar results were obtained in the present studies of endogenous zeatin level measurement, which increased gradually in normal root tips with increase in length of roots from 24 h to 120 h.
RNAs were prepared from normal shoot (shoot_0 h), normal root (root_0 h), shoot with salinity stress (shoot_1 h), or root with salinity stress (root_1 h).
Other genetic combinations resulted in a measly thale cress with shorter-than-normal roots.
Invertases may be particularly important in normal root development, since roots with disrupted vacuolar invertase function are typically shortened relative to wild type roots [ 32].
