Effects of plant growth promoting rhizobacteria (PGPR) on Citrus macrophylla rootstock

Citrus is one of the largest fruit crops grown in Morocco. Citrus crops gain in importance due to the jobs generated during the production process of fresh or processed fruit. Intensive agriculture is characterized by the excessive use of inorganic fertilizers and pesticides. This production system has generated serious environmental contamination problems, thus, it is necessary to implement sustainable production strategies to reduce the use of synthetic chemicals and contribute to soil and water conservation. In this context, Seventy two Rhizobacterial isolates of fluorescent Pseudomonas were isolated from rhizosphere soil of Citrus in the Sapiama nursery. These isolates were tested on germination and growth of Citrus macrophylla rootstock. The results obtained showed that the isolate C11 significantly stimulated germination 16 days after seed inoculation. The C26, C6 and C24 isolates showed PGPR effects improving significantly the growth parameters of C. macrophylla rootstock. They significantly promoted plant height, collar diameter and root length. This study concluded that the Pseudomonas isolates could be potential alternative biofertilizers to chemical products and could be considered as a promising main component for sustainable agriculture development strategy in Citrus farming. Keywords: Citrus macrophylla, Pseudomonas, PGP

Ova fatty acids composition and spawning performances of silver carp, Hypophthalmichthys molitrix (Morocco).

The present study is performed in order to determine the relationship between fatty acid (FA) profile of silver carp (Hypophthalmichthys molitrix) eggs and fertilization success, embryos viability and larval production. Mature unfertilized ova were collected during the reproductive season from 23 mature and healthy females, reared in Deroua fish farm (Morocco). Total lipids were extracted from ova sample and subjected to trans-esterification then the resulting fatty acids methyl esters were analyzed by gas chromatography tandem mass spectrometry (GC/MS/MS). The results showed that silver carp ova are dominated on total FA by docosahexaenoic acid (DHA) (21.21%) followed by oleic acid (21.07%), palmitic acid (17.71%) and eicosapentaenoic acid (EPA) (10.25%). During the breeding season, polyunsaturateds (PUFAs), monounsaturateds (MUFAs) and saturated fatty acids (SFA) didn’t show any significant difference. Moreover, within the PUFAs, the n-3 series were more abundant than the n-6 series, the total mean was 31.57 ± 1.01% and 5.33 ± 0.32%, respectively. No correlation was between fatty acids and the fertilization success. Maternal weight has effect on the levels of oleic acid (C18:1), arachidonic acid (C20:4) and docosahexaenoic acid (C22:6) in the egg whereas levels of palmetoleic acid (C16:1), eicosapentaenoic cid (C20:5) and docosahexaenoic acid (C22:6) are related to female age