Since algae is one of the natural sources of chemical compounds, including nutrients, fats and vitamins, thatstimulate the germination and growth of plants, so the aim of the research was to study the effect of aqueous extracts of Cladophora and Spirogyra at a concentration of (0, 1, 2) % in the germination and growth of three cultivars of the bread wheat Triticum aestivum (Baraka, Buhooth-22 and Sham-6) through the application of the pots experiment. The results showed that the aqueous extract of the algae affected positive  the assessed variables increase considerably as the concentration increased, and treatments at concentration (1 and 2%) had an encouraging effect on the germination and growth of plants of both cultivars  Buhooth-22 and Baraka, while cultivar Sham-6 was less responsive to the extracts.

Green algae constitute the most heterogeneous group of photoautotrophic protoctists inhabiting the biosphere and show an enormously wide variability of shape, size, and habit, and even color may be highly variable. According to the most recent taxonomic tree, the green algae have evolved in two major lineages; the chlorophytes clade (e.g. Cladophora, Chlamydomonas) and the Charophytes clade (e.g. Chara, Spirogyra). The first one includes the majority that is called "green algae'', whereas the second contains a smaller number of green algal; taxa Green algae. All are photoautotrophic and their growth depends on nutrients and underwater light availability, which is linked to physical parameters such as transparency, hydrodynamics, temperature, conductivity, and others .Those organisms have dimensions ranging from few micrometers to several centimeters with a substantial difference in their morphological organization from swimming or non-motile unicells ARTICLE INFO

Different methods to biosynthesis of Gold nanoparticles was done with using cyanobacterium Lyngbya sp. , and salt  gold  (HAuCL4) and evaluate their antibacterial activity .Gold nanoparticles were prepared in different ways ,dry and fresh weight of this cyanobacterium to obtain aqueous extract. The synthesized nanoparticles were characterized using analytical techniques such as UV-Visible spectroscopy, SEM (Scanning Electron Microscopy), FTIR (Fourier Transform Infrared) and XRD (X-Ray Diffraction). UV-visible spectroscopy show a Surface Plasmon Resonance (SPR) peak at (532- 552) nm; confirmed by (SEM) image revealed the spherical shape and the size range from (39.1-61.9) and (59.4-84.0) nm for dry, wet aqueous extract respectively. FTIR result showed containing of ( phenol ,protein and carbonyl) as afunctional group. The crystalline nature of the nanoparticles was evident from Peaks in the (XRD) pattern. biosynthesis

Microalgae are living microorganisms characterized by their ability to form a wide range of high-valued, bioactive compounds using sunlight, CO 2 and water (Al-Hayali & Al-Katib, 2020). Among these microorganisms, green microalgae constitute the most heterogeneous group of phototrophic primitives, which is considered one of the main sources of chemical compounds including nutrients, fats and vitamins (Khorshed & Al-Katib, 2021; Yaqub et al., 2022). In general, microalgae are among the richest biological sources of bioactive compounds produced from secondary metabolism and they are key sources of several phenolics, alkaloids and carotenoids (Al-Taie & Al-Katib, 2020). Nowadays, a great attention has been drawn to exploit the ecofriendly algae-mediated nanoparticles as powerful antimicrobial agents to manage and control human and plant diseases.