RESUMEN
Phytophthora spp. are the most serious threat to citrus industry worldwide. Being a soil borne problem, use of tolerant rootstocks is the most ecofriendly approach to manage the deadly diseases caused by this fungus. Here, we assessed the reaction of eight citrus rootstock genotypes including sour orange, Troyer citrange and six variants of C. jambhiri Lush. viz., RLC-5, RLC-6, RLC-7, Grambiri, rough lemon and Italian rough lemon against the inoculation of Phytophthora nicotianae. Inoculation of P. nicotianae infected the feeder roots of tested rootstocks to varying degree, expressing higher disease incidence (81.25%) and number of infected feeder roots (54.25-60.62%) depending on the rootstock. Troyer citrange and sour orange proved most tolerant rootstocks against the inoculated fungus. Phytophthora inoculation tended to increase the levels of reactive oxygen species (H2O2 and O2-), antioxidant enzymes (catalase, peroxidase, glutathione reductase, superoxide dismutase and β-1,3-glucanase) and protein content. However, it significantly reduced the levels of macro- (N, P, K Ca and Mg) and micro- (Cu and Zn) nutrients, although the extent of variation was rootstock specific. Overall, Troyer citrange and sour orange expressed the lowest variation in the levels of ROS, peroxidase (POX), superoxide dismutase (SOD) and β-1,3-glucanase, protein and nutrient contents, while rough lemon proved most strongly affected. Of the various variants of Citrus jambhiri, RLC-5 and Italian rough lemon proved more tolerant for Phytophthora nicotianae than rest of the clones tested.
RESUMEN
Ginkgo biloba has been used in traditional Chinese medicine for about 5000 years. A standardized preparation, EGb 761 has been recently prepared. The pharmacologically active constituents, flavonol glycosides and the terpene lactones are standardized. The terpene lactones comprise of ginkgolides A, B, C and bilobalides. The extract scavenges excess free radicals and pretreatment with EGb 761 reduces damage by free radicals in patients undergoing coronary bypass surgery. The action of platelet activating factor is antagonized and platelet aggregation is reduced. Blood flow is increased. Release of prostacyclines and nitric oxide was shown to be stimulated. Ginkgo biloba has been found to be useful in the treatment of Alzheimers disease and cognitive impairment. EGB 761 has shown beneficial effect in aging and mild cognitive impairment. Bilobalide has been shown to be protective against glutamate-induced excitotoxic neuronal death. Early studies indicate a potential role in age-related macular degeneration and some types of glaucoma. Anticancer action is related to antioxidant, anti-angiogenic and gene regulatory actions. Ginkgo biloba has shown overall improvement in about 65% of patients with cerebral impairment and a similar percentage suffering from peripheral vascular diseases. A recent study suggested that phytoestrogens in Ginkgo biloba may have a role as alternative hormone replacement therapy. Recent trials have not shown a beneficial effect of Ginkgo biloba in tinnitus and acute mountain sickness. Ginkgo biloba increased the bioavailability of diltiazem. The extract has been shown to protect against doxorubicin-induced cardiotoxicity and gentamicin-induced nephrotoxicity in animals. Ginkgo biloba inhibits microsomal enzymes and has a potential for drug interactions. Further studies to establish the efficacy of Ginkgo biloba are required.