Effects of nymphal density (Bactericera trigonica) and feeding on photosynthetic pigments,proline content and phenolic compounds in carrot plants

European Journal of Plant Pathology - Insect feeding induces physiological and biochemical changes in host plants. Indeed, symptom severity often depends on insect density. Recently, the carrot...     

Does olive mill wastewater stimulate olive plants growth?

Olive mill wastewater (OMW) is annually produced in enormous quantities and it constitutes a serious environmental problem. For several years OMW was used as an amendment in olive orchards which given beneficial effects on growth and soil properties. The present work aimed to study the effect of OMW used after one year from the oil extraction, where phenol content decreased. One-year-old plants of “Chemlali” olive cultivar were subjected to three treatments. C0, C1, and C2 were respectively 0%, 30%, and 45% of OMW used for amendment. Each rate was adjusted with water supplied every 15?days (1?L/plantlet). Results showed significant differences between treatments especially for growth, chlorophyll content of leaves (SPAD), and leaf nutrient content (P, K, Ca, and Na). Always C2 was better than C1. Substrate properties were clearly ameliorated particularly an increase of organic matter but the pH and the electric conductivity were unaffected.     

Potassium Mineral Nutrition Combined with Sustained Deficit Irrigation to Improve Yield and Quality of a Late Season Peach Cultivar (Prunus persica L. cv ‘Chatos’)

ABSTRACT

Fruit quality traits are directly related to agronomic practices such as irrigation and fertilization, especially potassium supply since its effects on quality and water drought resistance. The objective of this study was to evaluate the effect of different combinations of potassium rate and application mode (in soil: 200S and 100S, foliar spray: 100F) with two irrigation regimes (FI: irrigation with 100%ETc and DI: irrigation with 66%ETc) on peach yield and quality parameters. The experiment was performed during two consecutive years. At harvest, only in the second year significant differences between treatments were observed in yield. In fact, potassium foliar spray, even in DI regime, improved yield. The fruit diameter was slightly affected by treatments in the first year. However, in the following season foliar potassium spray even in DI water regime increased fruit size. Concerning the firmness, no significant differences were observed in the first year except for the second year it decreased with DI strategy independently of potassium treatment. The soluble solids content was strongly affected by the treatments. The highest values were observed in 100F+DI treatment with no significant effect on acidity. Vegetative growth was affected only by water regime which DI reduced shoot length.     

Factors affecting the milk yield and composition over lactation of prolific D’man ewes in Tunisian oases

This work aimed to investigate milk potentiality and the influence of some non-genetic factors both on milk yield production and composition in prolific D’man sheep. Observations were performed in eighty lactating D’man ewes maintained under an intensive oases system in Southern Tunisia. Daily milk yield was determined at 7-day intervals using oxytocin?+?hand milking method. Chemical milk composition was determined by Lactoscan. Total productions over lactation (milk, fat, and protein) were estimated using the Fleischmann method. Daily milk yield averaged 1.64?±?0.02 l. It increased to a plateau from the third to the fourth week of lactation, and decreased gradually to the tenth week. D’man ewes produced 128.91?±?3.14 l of milk, 9.23?±?0.26 kg of fat, and 5.26?±?0.12 kg of total proteins. Overall, milk contained 16.17% of total solids, 7.08% of fat, 4.04% of proteins, 4.32% of lactose, 9.09% of solids-not-fat, and 0.73% of ash. Lambing season affected the daily milk yield and milk composition, where fat and total proteins were highest in autumn. Total solids, lactose, solids-not-fat, and ash were higher in winter than in autumn and summer. Ewes reared multiple lambs produced more milk than those reared singles. Dams nursing triplets or more had the highest milk total proteins, and the lowest total solids and fat levels. Adult ewes produced more milk compared to younger and older ewes, and their milk contained higher total solids, fat, and ash levels than milk from young ewes. Ewes with asymmetric udder produced less and more concentrated milk than ewes with symmetrical udder. Daily milk yield was negatively correlated to total solids, fat, and total proteins amounts. In contrast, litter survival at weaning was positively correlated to the amounts of total milk, fat, and total proteins.

     

Potassium uptake efficiency of two pear cultivars and leaf concentration at deficiency symptoms appears

Two pear cultivars (Meski Ahrech and Alexandrine) grown in pot culture under normal daylight conditions in a greenhouse were submitted to potassium deficiency treatments. The potassium-free treatment decreased leaf K concentration, relative water content, SPAD, and gas exchange comparatively to the control. “Alexandrine” appeared more sensitive to potassium deficiency due to the main decrease in stomatal conductance (gs), photosynthesis (A) and transpiration (E) compared to “Meski Ahrech” that reduced only carbon assimilation (A). After 42 days of treatments, leaf K concentration in “Alexandrine” was 0.75% DM compared to 1.15% DM in “Meski Ahrech”, which appeared to be more efficient in potassium uptake.     

Factors affecting milk yield and composition of Tunisian camels (Camelus dromedarius) over complete lactation

This study aimed to investigate the milk production potential and the impact of nongenetic factors on milk yield and composition of Tunisian dromedary camels. Milk recording and sampling were carried out at monthly intervals over complete lactation for 3 years from 95 camels reared in intensive and semi-intensive systems. The overall means of daily milk yield and fat, protein, total solids, and ash contents were 4.21 ± 1.98 l/day, 2.45 ± 0.9%, 2.67 ± 0.74%, 10.75 ± 1.41%, and 0.85 ± 0.08%, respectively. The total milk yield was 1388.41 ± 575.46 l/lactation for 11 months of lactation. The daily milk yield increased regularly throughout lactation until it reached its peak in the 4th month postpartum and then decreased until the 17th month postpartum. The chemical components, except ash, followed an opposite trend to the milk yield. Their minimum contents were recorded during the 7th and 8th months postpartum, while the maximum levels were observed during the 17th month postpartum. Regarding seasonal variation, the highest daily milk yield was recorded during summer (June), whereas the lowest was found in winter (December). In contrast, the maximum and minimum contents of fat and protein were observed during winter (December) and summer (July), respectively. Similarly, total solids content was maximum in January and minimum in August. Parity had no effect on daily milk yield, while all chemical components were higher in milk from primiparous than multiparous camels. Calf sex and management system did not affect the milk yield and composition. These results are useful in order to develop feeding strategies and breeding programs for improving milk production.