Large cortical cell area, epidermal thickness, midrib thickness, vascular bundle area,
metaxylem area and spongy cell area in leaves increased in all Rosa species as contamination increased in irrigation waters and R.
brasiliensis root extract fractions displayed a more significant reduction in the average size of the
metaxylem cells compared to those grown in the presence of leaf extract fractions and the control solution (Figures 5 and 6).
[ha.sup.-1] significantly reduced the number of root
metaxylem vessel elements.
Metaxylem area varied significantly at p greater than 0.001 (Table 1) in all the cultivars of date palm (Phoenix dactylifera L.).
Vascular tissue--Four shapes of major vascular bundle are observed: ovoid (63), rhomboid (64), elliptical (65), round in outline (66); one or more vessels of
metaxylem are located either in the central part or in the lower part of the major vascular bundle (67, 68); location of phloem, only in the lower part of xylem (69), or surrounding it partially, either U-shaped (70) or half-moon shaped (71); fibers in major vascular bundle are either mostly located at the bottom (72), or located at the two extremities with a few laterally (73), or exclusively located at the extremities (74).
metaxylem and protoxylem, sclerenchyma sheath, parenchyma and fibers) were bigger for the disturbed site stem samples than for those from the undisturbed site (Tables 2 and 3).
However, with the exception of a few intact (but presumably nonfunctional)
metaxylem vessels, all areas of the crown core had disintegrated with only the outline of various cells visible (Fig.
Canny J (1988) Late maturation of large
metaxylem Vessels in soybean roots: significance for water and nutrient supply to the shoot.
Highest cortical thickness
metaxylem area and phloem area were observed in Makran.
The xylem is the principal water-conducting tissue of vascular plants and is divided in primary xylem which consists of protoxylem that has an active stretch in its youth and the
metaxylem which begins in the mature plant, but after elongation it is stretched and is destroyed.
Young or distal regions of wild rice adventitious roots have a stele with differentiating proto- and
metaxylem, a cortex with an endodermis, a midcortex with thick cell walls in inner layers, developing schizolysigenous aerenchyma, an enlarged outer ring of cells (not part of the hypodermis), a distinctly biseriate hypodermis, and an epidermis at 5 mm from the apex (Figure 1(a)).
Considering the diameter of
metaxylem vessels (XD), significantly greater mean diameters were observed during the rainy season in the joint analysis (Tables 3 and 4).
