الفهرس 
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Abstract
Pisum sativum plants were treated with two concentrations of ABA (10µM & 20 µM) in both vegetative stage and fruit stage (legume formation). Vegetative stage was treated via spraying of a one-month-old plant with ABA twice through 10 days interval between both sprays. Fruit stage was treated via injection of the legume with ABA at three different developmental stages (early, intermediate, and late). Their corresponding controls were sprayed/injected with diluted ethanol.
The main objective of this study is to decipher the role of some plant growth hormones during embryogenesis (i.e., seed formation in pea plants and correlate their impact on the physiological aspects and the expression of some selected genes responsible for the accumulation of seed storage proteins.
In the following, brief accounts for the main experimental results are given:
1. Phenotypic characterization
When ABA was sprayed on one month old plants during vegetative stage, it resulted in slight increase in the stem length in treatment B and decrease in treatment A compared with the control. However, these changes in stem length in both treatments were not statistically significant.
With regard to the diameter of ABA injected legume, during early and intermediate stages of legume development, the effect of A & B treatments was not that obvious as compared to the control. However, on late stage, both treatments resulted in an increase in the legume diameter. The highest concentration of ABA (treatment B) significantly increased the diameter of the treated legume at late stage.
whereas the L.S sections of fully mature seed exhibited larger diameter in treated plants with both treatments A&B at late stage as compared to the control but didn’t show any difference in the size of embryo nor endosperm.
2. Physiological parameters
Photosynthetic pigments
The photosynthetic pigments (chlorophyll (a), chlorophyll (b), chlorophyll (a+b) and carotenoids) were significantly increased with both treatments of ABA hormonal spray on the vegetative parts.
Total carbohydrates, total soluble sugars, and starch
Total carbohydrate content was significantly increased in both ABA sprayed vegetative leaves and yielded seeds of ABA injected legumes at the 3 developmental stages: early, intermediate and late.
Total soluble sugars content was significantly increased in vegetative leaves while the mature seeds showed that:
In Early stage, total soluble sugars decreased significantly with treatment B and increased with treatment A but with non-significant value, compared to the control.
In intermediate stage, total soluble sugars increased significantly with treatment A and decreased with treatment B but with non-significant value, compared to the control.
In late stage, both treatments didn’t effect on the total soluble sugars with significant values.
Starch content measured in the yielded seeds of ABA injected legumes showed significant increase with both ABA treatment at the 3 developmental stages.
Total phenolic
There is a significant increase in the phenolic content with both treatments of ABA hormonal spray on the vegetative parts.
Endogenous hormone
The exogenous ABA application (A&B) reduced the endogenous content of IAA, GA and cytokinin of the pea leaves and seeds, while the total endogenous content of ABA increased.
Mineral content (K, Mg & Ca)
Treatment B of ABA elevated the potassium, magnesium, and calcium contents in all stages with significant values. Treatment A elevated the potassium and magnesium contents significantly in all stages but the calcium content increased significantly in early and late stage only and increased in intermediate stage but with non-significant value.
Protein concentration and amino acids
In vegetative leaves, both ABA treatments A and B increased the protein constituents (total proteins, free amino acids, and proline) significantly.
In seeds, Both ABA treatments elevate protein concentration in all stages with significant values.
SDS-PAGE protein profile indicates an increase of some major pea proteins in relation to treatment A and B application. The effect was also the highest in applications of late stages. The intensity of Convicilin , Vicilin and legumin bands increased and were directly proportional with the concentration of ABA as compared to the control within the same stage. This increase was the highest when ABA was applied during the late stage. On the other hand, other protein bands such as lipoxygenase, Vicilin, Legumin β and Lectin β exhibited slight change in their expression compared with the control.
Amino acid profile
general, treating pea plants with abscisic acid at concentrations of 10 and 20 µM during the three stages of embryogenesis elevated total amino acids constituents. The magnitude of increments was increased with increasing Abscisic acid concentrations especially at the late developmental stages which markedly increased phenylalanine and lysine amino acids as compared with their corresponding control and respectively. Moreover, the ratio of the essential to non-essential amino acids was increased in response to the above-mentioned treatments as compared with that of the corresponding controls under the three developmental stages (early, intermediate and late stages).
3. Genetic analysis
One step reverse transcription polymerase chain reaction
It is observed that the expression level of vicilin and legumin in the plants treated with 20 µM ABA was upregulated from the basal expression level of their control. Tubulin was successfully represented in all samples tested as a house keeping gene.