الفهرس 
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Abstract
Gladiolus grandiflorus belongs to family Iridaceae. It is one of the important ornamental bulbous plants. It has decorative spike which carries numerous florets. Its flowers are excellent attractive cut flowers, (Pant, 2005) which are needed for local markets in winter and spring, as well as, for export to foreign ones. In addition, gladiolus plants are commonly used in borders and beds of many gardens. In this study, gladiolus grandiflorus Cv. Eurovision was chosen for its popularity and adaptability. to Egyptian environmental conditions.
A field experiment was carried out during the two successive seasons of 2016/2017 and 2017/2018 at the nursery and laboratory of Ornamental plants, Fac. of Agric., Minia University. The aim of this study was to figure out the effect of humic acid (HA), boric acid (BA) and/or potassium silicate (PSi), as well as, their interaction on vegetative growth, flowering aspects, corm and cormels production and some chemical constituents of gladiolus grandiflorus cv. Eurovision plants. The experiment was arranged in a randomized complete block design in split plot design with three replicates. The main plots (A) included three levels of HA (0, 0.25 and 0.50 g/l), while the sub-plots (B) included seven treatments (BA at 25 and 50 mg/l, PSi at 50 and 100 mg/l and. B/Si at low and high levels of both substances). Data were recorded for number of leaves /plant, leaf length, width and aired leaf fresh and dry weights, flowering date, spike length, diameter and fresh and dry weights, number of florets/spike, length of flowering part of spike, flower diameter and fresh and dry weights, corm diameter and fresh weight, cormels number and fresh weight, as well. as, photosynthetic pigments and N, P and K % in the leaves.
The most important results could be summarized as Follows.
Vegetative growth characters:
Different vegetative growth characters of gladiolus grandiflorus cv. Eurovision were greatly and significantly increased due to the application of humic acid (HA) at both low and high levels. The high level was much more effective than the low one for all studied traits.
Boric acid and/or PSi were also effective in promoting different vegetative growth characters, with the dual BA/PSi treatments giving the highest values, followed by Si treatments while BA treatments gave the least values.
Combining humic acid with BA/PSi resulted in the highest overall values of vegetative growth. over those of either humic acid or boric and/or silicon treatments.
II. Flowering parameters
Humic acid, especially at the high level, was very effective in producing better flowering quantity and quality of gladiolus plants, except in delaying flowering date and affecting the length of flowering part of the spike. The most pronounced results were observed for spike length, diameter and fresh and dry weights, as well flower diameter and it fresh and dry weights.
Similarly, boric acid and /or potassium silicate treatments. augmented different flowering aspects particularly the combined BA/PSi at the high level. In contrast, flowering date was delayed and number of florets/spike and length of flowering part/spike were not affected.
The combined treatments of humic acid plus boric acid and potassium silicate at the high level each produced the maximum flowering quantity and quality aspects those were positively augmented by humic acid, as well as, boric acid/potassium silicate treatments.
III. Corm and cormels production:
Positive and pronounce effect of humic acid on vegetative growth and flowering aspects of gladiolus plants was continually exceeded to corm production in sort of corm diameter and fresh weight and cormels number and fresh weight. The high humic acid level proved to be always much more effective than the low level.
The dual boric acid/potassium silicate treatments caused noticeable increase on corm diameter and fresh weight of corm and cormels. It was clear that supplying gladiolus plants with both humic acid and dual boric acid/silicon caused great and remarkable increase in corm and cormels production.
IV Chemical constituents:
IV-1 Photosynthetic pigments:
The three photosynthetic pigments, chlorophyll a, chlorophyll b and carotenoids contents were greatly stimulated by each of humic acid, boric acid and /or silicon and more pronouncly by all of them when added simultaneously to the gladiolus grandiflorus cv. Eurovision under this study.
IV-II: Leaves N, P and K %
The response of the three photosynthetic pigments to each of humic acid or boric acid and/or silicon, as well as their possible combinations was shown also for each of nitrogen, phosphorus and potassium % in the leaves of gladiolus plants. The high level of humic acid in combination with the high boric acid/silicon resulted. in the highest values of leaves N, P and K %.