Significant differences were observed due to genotypes for stomatal density, SSC and PCI and estimation of operating stomatal conductance (gs).The genotypes and irrigations regimes interaction was significant for all the measured traits (Table 2 and 3).Holland and Richardson (2009) showed that stomatal density and guard cell
length are both sensitive to environmental conditions and that considerable genotypic variation and phenotypic plasticity occurred in these traits.
On the other hand, the mean lengths ([micro]m) of guard cells
at the upper epidermis of the non-polluted populations, were 1.23 [+ or -] 0.86,2.93 [+ or -] 0.18 and 2.89 [+ or -] 0.34 at Ebvomodu, Ebvoneka and Eyaen respectively while at the lower epidermis the mean lengths ([micro]m) were 1.40 [+ or -] 0.91, 2.12 [+ or -] 0.41 and 2.01 [+ or -] 0.60, respectively.
Cell size measurement: Size (Length & breadth) of epidermal cells and guard cells
were measured with ocular micrometer under high power magnifications with the help of "stage-ocular micro-metery" and "Motic Images plus 2.0 ML" software.
In yucca, the stoma are circular or elliptic with two large, extended guard cells
covering the stoma (Figs.
Therefore both ROS and NO are produced in response to pathogen attack (Dumer & Klessig, 1999) and also in guard cells
in response to ABA (Neill et al., 2002a).
Zhang and Outlaw (2001) reported that stressing Vicia faba roots could change ABA concentrations at the guard cell
apoplast and that the apoplastic guard cell
ABA concentration correlated with changes in stomatal aperture more effectively than did the guard cell
Intrinsic water use efficiency did not change significantly over time, suggesting that it may not respond to changes in CO2 concentrations over the lifetimes of individual trees, possibly because of compensating changes in stomatal density and guard cell
The two guard cells
surround the central pore through which water is lost by plants.
These consistently showed that stomata occurred in rows and were paracytic--the stomata were bordered by two subsidiary cells with their longitudinal axes parallel to those of the stomal pore and guard cells
(Prabhakar 2004), although they can be tetracytic as well (Ruddall and Chase 1996) i.e.
In her first body paragraph, Bridget focused on each of the two cells in turn: firstly root hair cells and then guard cells
. This type of patterning of themes across a text contributes to the text's predictability' (Humphrey & Droga, 2003, p.
In all treatments, in an environment with natural light, the stomata have guard cells
with external periclinal walls that present a rather sharp thickening, forming a crest around the external atrium, and underdeveloped substomatic chambers (Figures 3A, E, 4A, C, D).
Epidermal cell shape and thickness; stomata type, location, and distribution; trichomes shape, size, and distribution; the arrangement and position of accessory cells surrounding the guard cells
as well as the type of phloem and xylem vessels present were the qualitative features considered.
A variety of characters like epidermal cells, subsidiary cells, guard cells
, trichomes, macro-hairs, micro-hairs and stomata were used as a tool for the taxonomic grouping of different species.