Journal of Plant Process and Function

Water deficit is a common and major constrain for agricultural production in arid and semi-arid parts of the world like Iran, to the extent that it might threaten the nation’s food security in years to come. Seed germination is a crucial growth stage that is often affected by environmental stresses, including drought. This study investigated the effects of four levels of water potential (i.e. 0, -0.2, -0.4 and -0.6 MPa) on germination, seedling characteristics, soluble carbohydrates, proline and polyphenols contents, and antioxidant enzymes activities of 12 fennel genotypes. Low water potentials reduced germination percentage and speed of germination, seedling fresh and dry masses, shoot length and superoxide dismutase specific activity, though it led to increases in root length, soluble carbohydrates, proline and polyphenols contents, and catalase specific activity. The 12 genotypes according to the degree of decreases in germination percentage at -0.6 MPa compared to control, were classified into three groups, including drought-tolerant (Shiraz, Yazd, Kerman and Mashhad), moderately-tolerant (Hamadan, Kashan, Bushehr and Urmia) and drought-sensitive (Birjand, Ardabil, AviSina and Isfahan). Mashhad, as a drought-tolerant genotype, indicated the greatest germination percentage, seedling fresh and dry masses, root length, soluble carbohydrates, proline and polyphenols contents, and catalase and superoxide dismutase specific activities among 12 genotypes studied. The results obtained in this study demonstrate some key aspects of the drought tolerance-related characteristics of fennel at germination stage that may help elucidate the whole plant performance of fennel at drought-stricken areas, when integrated with results from field studies.

Due to the increasing production of nanoparticles in recent years and their applications in various applications such as medicine, imaging, catalysts, semiconductors, cosmetics, microelectronics, coatings on various materials, etc., there are currently concerns about the potential hazard and environmental pollution. Nanoparticles have been created globally. The purpose of this study was to investigate the effect of copper oxide nanoparticle toxicity on the activity of some antioxidant enzymes, protein and germination indices of canola, and also to investigate the effects of humic acid on nanoparticle toxicity in laboratory environment. An experiment was conducted at the germination stage of rapeseed (Octopus cultivar) to investigate the effect of copper oxide nanoparticles in concentrations of 0, 250, 500, 750, 1000, 1250, 1500, 1750, 2000 mg per liter and humic acid in concentrations of 0, 100 mg / L, in 3 replicates, a factorial in a completely randomized design. The results showed that, with increasing concentrations of copper oxide nanoparticles, the levels of activity of all four superoxide dismutase enzymes, ascorbate peroxidase, catalase and peroxidase increased (5.00, 2.9, 2.00, 2.35), respectively, but the amount of protein 2 times lower. Germination indices (root length, stem length) also decreased (39.3, 56.6, 12.7), respectively. The use of humic acid reduced the toxicity effects of copper oxide nanoparticles, especially at the level of 2000 mg / L, so that the root length, stem, root and shoot stomatal length (respectively) 68/9, 0/3, 0/6, 5/5) decreased compared to the control. It can be stated that humic acid can increase the activity of antioxidant enzymes and increase growth by increasing the activity of quasi-hormonal activity.