Browsing by Author "Ahmad K. Hegazy"

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Energy content of plant organs and population cohorts in Moringa peregrina: concepts for species conservation management in arid regions
(Egyptian Academy of Science and Technology, 2024-12-01) Ahmad K. Hegazy; Mohammad K. Okla; Zahra S. Husein
Conservation management and sustainable use of Moringa peregrina are needed to overcome overexploitation coupled with potential environmental changes. This study demonstrates the energy dynamics of M. peregrina, how stored energy influences species persistence amidst environmental challenges, and the importance of energy reserves in the resilience of the species population. Field, greenhouse, and lab experiments were conducted at the levels of population cohorts, plant organs, seeds, and seedlings to demonstrate the relationship between energy content and the persistence of the species. Seedlings and juveniles stored around 12,000 joule/g in roots, while uncoppiced adults stored about 9,000 joule/g in stems, and coppiced adults stored 1,800-4,000 joule/g in lignotubers. In adult trees, the number of sprouting stems is correlated with the energy content in lignotubers. Over the ten years of seed storage, a rapid rate of energy depletion was observed, ranging from 16,821 to 5,059 joule/g, which is associated with decreased germination and viability. The energy content in two-month-old seedlings varied from 240 to 800 joule/seedlings under 200 and 800 mm rainfall, respectively. The unstable population structure could be ascribed to the depletion of stored energy in lignotubers following uncontrolled coppicing and the rapid depletion of seed energy, which hinders the population resilience.
Molecular variations and photosynthetic pigment content of Avicennia marina growing in subtropical habitat types
(Egyptian Academy of Science and Technology, 2024-12-01) Samar S. Marae; Ahmad K. Hegazy; Merit Rostom; Zahra S. Hussein; Hossam E. A. Awad
Mangrove habitats are important ecosystems for their ecological value, and goods and services they offer. These costal habitats are currently vulnerable due to excessive human activities. The black mangrove Avicennia marina (Forssk.) Vierh. (Avicenniaceae) populations growing in Nabq protected area represents the northernmost latitudinal limit of the Indo-Pacific-East African naturally growing mangrove forests. In this study, nine A. marina populations inhabiting Gulf of Aqaba were studied to assess the genetic relationship among the populations by Start Codon Targeted (SCoT) and Inter Simple Sequence Repeat (ISSR) as DNA Markers. Variations of photosynthetic pigment content were assessed in the populations growing in different habitat types. The numbers of polymorphic bands were 18 and 6 for SCoT and ISSR, respectively. The percentage of polymorphism showed wide range amounted to 40.9 for SCoT and 25 for ISSR, while the number of amplicon bands ranged from 8–10 in SCoT and 2-9 in ISSR. The genetic relationships among populations using SCoT and ISSR analysis showed close relationship between the nearby but different habitat type populations such as sand mound and littoral populations, or between populations of same habitat types in the study region. The photosynthetic pigment content of chlorophyll a and b, and carotenoids in the littoral and intertidal populations were higher than that in the sand mound and salt plain populations. Populations inhabiting Nabq protected area have wide range of polymorphism among different habitat types. Further studies are required to investigate the genetic relationships among populations of A. marina inhabiting the eastern and western sides of the Red Sea.