This investigation was carried out during the two successive seasons of 2006 and 2007 at the Agricultural Experimental and Research Station, Faculty of Agriculture, Cairo University Giza, Egypt. to study the effect of IAA and BA on vegetative growth and yield of soybean plant. Three concentrations, 50,100 and 200 ppm. were used of each growth regulator. The results revealed that IAA or BA increased main stem length, number of branches and leaves per plant, dry weight of leaves, stems and pods per plant, number of mature pods and seeds per plant and seed yield per plant. Number of main stem internodes, total leaf area per plant and weight of 100 seeds were not affected by treatment.

Seedlings of Vigna radiata (L.) Wilczek (Mung bean) were examined by light microscopy to study vascular development through the transition region. The beginning of vascular transition took place about one centimeter below the soil surface by the appearance of a pith between the large central vessels. At the higher level, pith parenchyma increased and the vessels are separated into four groups. The protoxylem maintains its peripheral position, but the metaxylem instead of differentiating toward the center, diverges laterally from the protoxylem. At successively higher levels, the hypocotyl axis widens and the distances between the protoxylem poles as well as the divergence of each xylem arms increased. The reorientation of primary xylem took place gradually upward. The length of the transition region from a point where the axis is exarch and protostele to a point where the xylem form approximately endarch condition was about two centimeter. Thus, most stages of vascular transition in mung bean seedling occur in the lower portion of the hypocotyl, and the reorientation of vascular tissue from exarch radial to the endarch collateral arrangement may be completed in the upper portion of the hypocotyl.The behavior of vascular cambium activity and the difference in maturation degree at the different levels of the hypocotyl indicating that the upper portion of mung bean hypocotyl is older than the lower one. Adventitious root primordia were recorded at the basal portion of hypocotyl and their development was associated with the activity of vascular cambium.

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GA3 or PCPAA significantly increased stem length, internode length, dry weight of stem or leaves per plant, but slightly increased number of stem internodes.CCC significantly decreased stem length, internode length, dry weight of stem or leaves per plant but slightly decreased number of internodes.Transverse sections in the uppermost internode of sorghum stem revealed that GA3 induced more thickening and lignification in cell walls of different tissues, increased the amount of phloem per vascular bundles, promoted cell elongation and radial enlargement of ground parenchyma cells. CCC treatment showed retardation in thickening and lignification of vessels and peripheral mechanical tissue cell walls, maturation of ground tissue and elongation of ground tissue parenchyma cells.PCPAA increased the size of vascular bundle due to adnation of two adjacent bundles, or to the increase in the amount of vascular tissues of the individual bundle, and promoted cell elongation of the ground parenchyma.GA3 and PCPAA promoted protein synthesis while CCC inhibited it in the two cultivars. GA3, PCPAA and CCC decreased total carbohydrates and crude fibers in grains of the two cultivars. Effect of growth regulators on ash percentage in sorghum grains varied to some extent according to cultivar and growth regulator used.