DIRECT SCIENCES: SOLVING PROBLEMS THROUGH SCIENTIFIC NETWORKING

Mango is a major fruit crop of Sindh. In recent past death in mango has caused massive losses in its production. In order to find the preventive measures for this disease efficacy of plant extracts was evaluated in this experiment. Botanical extracts of five plants i.e. neem (Azadirachta indica), ak (Calotropis procera), dhatura ( Nicotiana tabacum) and onion (Allium cepa) were used. These extracts were tested in vitro in four concentrations 2ml, 5ml, 10ml, 20ml per liter of nutrient media in three replicates using completely randomized design. The results revealed that plant extracts considerably inhibited mycellial growth of test fungus as compared to control. Neem extract was the most effective and it produced 84.29% inhibition followed by tobacco with 74.84% reduction in fungal growth. Minimum reduction (53.428%) of Ceratocystis fimbriata was observed in dhatura extracts. The use of these extracts especially neem can be fruitful in eco management of sudden death in mango

Sudden death, Mango, Plant extracts, Management

The present work aimed to study the floristic composition and species diversity of weed assemblages in citrus orchards in Aljouf region, Kingdom of Saudi Arabia. Floristic lists were prepared and species coverage values were determined in 20 stands, using ten quadrats (1 × 1 m) per stand. In total, 33 plant species belonging to 15 families and 30 genera were identified. The largest families were Asteraceae and Poaceae (5 species for each), followed by Fabaceae (4 species), Chenopodiaceae and Polygonaceae (3 species for each). Therophytes represented the dominant life form (66.7% of the total flora), followed by geophytes (12.1%), chamaephytes, hemicryptophytes (9.1% for each) and phanerophytes (3%). The application of TWINSPAN (Two Way Indicator Species Analysis) classified the weed vegetation into four groups dominated by Plantago lagopus, Cynodon dactylon, Imperata cylindrica and Convolvulus arvensis. The species richness for the vegetation group dominated by Plantago lagopus was significantly higher (15.8 species/stand) than for the other vegetation groups. Shannon index and evenness did not show significant differences among the different vegetation groups. The species richness of citrus orchards was relatively high which could be related to the environmental heterogeneity due to different light conditions in citrus orchards.

Agricultural systems, Species diversity, Life form, Plant communities

The effect of allelochemicals from Casuarina cunninghamiana branchlets was assessed on the growth and metabolomic content of three recipient plants: (cucumber), Lycopersicon esculentum Mill.(tomato) and Brassica nigra L. (black mustard). The aqueous extract delayed the germination rates of the three species with pronounced effect on B nigra and L. esculentum.The aqueous extract significantly reduced the seeds germination percentage of B. nigra. The shoot and root lengths were reduced significantly under these concentrations and the germination index (GI) registered lower value due to the effect of the extract on root length. Under these concentrations (1-4 %) the seeds germination percentage of L. esculentum was not significantly affected but the root length was dramatically decreased. No significant change either in seeds germination percentage or in the root length up to the concentration of 4 % was recognized in .Application of allelochemicals from germination and growth criteria but also affected the biochemical and metabolomic content in C. sativus. Application of allelochemicals from C. cunninghamiana branchlets not only affected the germination and growth criteria but also affected the biochemical and metabolomic content in the recipient crop species. A significant increase in carbohydrates, proteins and was also observed in L. esculentum and proline content was observed in both plants. Stress on germinated crop seeds resulted in a significant decrease in photosynthetic pigmen cunninghamiana branchets aqueous extract in both plants but the content was increased significantly under the highest concentration in tomato. Sensitivity of the weed allelochemicals from the donner plant may open the door to exploit overcome the growth of weeds species associated to crop plants through using this plant as natural herbicides

Allelopathy,Casuarina cunninghamiana,Cucumis sativus,Germination percentage,Lycopersicon esculentum, Root length, Shoot length, PCA