Influence of Benzyladenine on Leaf Senescence and Photosynthesis in Sunflower (Helianthus annuus L.)

The effect of foliar application of benzyladenine on sunflower leaf senescence, photosynthesis, RuBP carboxylase activity and diffusion resistance was investigated. A considerable drop in photosynthetic rate and rise in diffusion resistance were noted dunng the seed filling period. Benzyladenine application maintained the chlorophyll content and chlorophyll a : b ratio at higher level, enhanced RuBP carboxylase activity and net photosynthesis in both upper and lower leaves. A lower level of diffusion resistance was also observed by benzyladenine application during seed filling period. The results suggested that application of benzyladenine at 30, 60 and 90 days after sowing could help to maintain photosynthesis and assimilate supply to the developing seeds of sunflower.     

The Fusarium graminearum genome reveals a link between localized polymorphism and pathogen specialization

We sequenced and annotated the genome of the filamentous fungus Fusarium graminearum, a major pathogen of cultivated cereals. Very few repetitive sequences were detected, and the process of repeat-induced point mutation, in which duplicated sequences are subject to extensive mutation, may partially account for the reduced repeat content and apparent low number of paralogous (ancestrally duplicated) genes. A second strain of F. graminearum contained more than 10,000 single-nucleotide polymorphisms, which were frequently located near telomeres and within other discrete chromosomal segments. Many highly polymorphic regions contained sets of genes implicated in plant-fungus interactions and were unusually divergent, with higher rates of recombination. These regions of genome innovation may result from selection due to interactions of F. graminearum with its plant hosts.     

Evapotranspiration losses for pepper under plastic mulch and shallow water table conditions

Use of literature crop coefficient (K _c) values for quantifying evapotranspiration (ET_c) under non-standard conditions such as plastic mulch, shallow water table, and sub-tropical conditions can lead to inaccurate ET_c estimates. A 5-year experiment was conducted for fall crop growing seasons in south Florida to quantity bi-weekly ET_c and K _c for bell pepper grown under shallow water table and plastic mulch environments using large drainage lysimeters. The ET_c values varied from 205 to 320 mm with a seasonal average of 267 mm. Average K _c values for bell pepper for development, mid-season, and late stages were 1.05, 1.21, and 1.28, respectively. Higher than literature initial K _c values were due to rainfall and use of sub-irrigation system to maintain artificially high water table which results in high soil moisture in the bare soil area—such high moisture results in high evaporation. The K _c values from this study were statistically higher than literature values. Use of literature K _c values resulted in underestimating ET_c by 27–37%. The K _c values would provide improved estimates of sub-irrigated pepper ET_c in subtropical Florida and elsewhere with similar environment.     

Standardization of Rootstocks of Mango (Mangifera Indica L.)

Mango cuttings could be induced to form roots provided IBA at 5,000 p.p.m. in lanolin was applied at the base of shoots after removing a ring of bark while they were still attached to the mother tree.

Cuttings taken from one-month-old seedlings gave the highest percentage of rooting and establishment, but with increasing age of the mother plants the rooting was considerably reduced. The rooting of cuttings of different age groups could be improved by using shoots forced into vigorous growth by hard pruning. Younger plants responded better to such treatment than older ones.

Cuttings from etiolated shoots rooted better than those from non-etiolated, but etiolation was less effective in promoting rooting than invigoration by hard pruning. Etiolation and invigoration combined gave the highest percentage of rooting and establishment in all age groups.     

Bekämpfung von Epilachna vigintioctopunctata (F.) und Spodoptera litura (F.) mit Silikaten

The present work deals with the insecticidal efficacy of different modified natural silica products against the field pests Epilachna vigintioctopunctata (F.) and Spodoptera litura (F.). The substances “Fossil Shield^® 90.0s”, “Advasan^®” as well as different formulations of a silica-derived substance named “AL06” (developed in the section Urban Horticulture, Humboldt-University Berlin) were dusted into gauze-covered cages. In each cage, test insects were placed and mortality measured over time. A 100% mortality rate was archieved two days after treatment of adult E. vigintioctopunctata and S. litura larvae with some silica “AL06”-formulations. In contrast, mortality rate for E. vigintioctopunctata larva was only 30 to 70% after two days of treatment. Mortality rate was dose dependend, even though a linear correlation could not be found. Furthermore, the commercial substance “Advasan^®” was able to control the horticultural pest E. vigintioctopunctata within 48 hours successfully. For future horticultural applications, possible phytotoxic side effects of silica dusts and an application technology resulting in adequate leaf coverage have to be considered.     

Antifeedant activity and toxicity of leaf extracts from <Emphasis Type="Italic">Porteresia coarctata</Emphasis> Takeoka and their effects on the physiology of <Emphasis Type="Italic">Spodoptera litura</Emphasis> (F.)

Antifeeding and toxic effects of chemical extracts from Porteresia coarctata Takeoka on the insect pest Spodoptera litura (F.) were investigated in the laboratory. Hexane extracts of P. coarctata leaves were re-dissolved in dimethyl sulfoxide and applied in water to leaves of Ricinus communis L. (castor). A concentration of 1,000 and 2,000 ppm extract exhibited significant antifeeding and toxic effects to third instar larvae when compared to the same concentration of dimethyl sulfoxide in water as control. One day after feeding on extract-treated castor leaves, the mortality of S. litura larvae was 50%. Mortality increased to 95% after 11 days at a dosage of 2,000 ppm. Compared to the control, third instar larvae fed on castor leaves treated with P. coarctata leaf extract at different concentrations showed significant reduction in protein and DNA content in the fat body and midgut tissues. Results demonstrate the insecticidal and antifeedant properties of P. coarctata leaf extract against the generalist pest S. litura leading to biochemical changes in the insect body. Thus, P. coarctata contains phytochemicals, and the extract, in crude and pure form, has potential as a botanical insecticide in alternative control strategies against Lepidoptera pests.     

Effects of supplementation of medium with different antioxidants during in vitro maturation of bovine oocytes on subsequent embryo production

The aim of this study was to assess the effects of different antioxidants on the levels of reactive oxygen species (ROS) and glutathione (GSH) in oocytes during in vitro maturation (IVM), as well as on the production of embryos. Oocyte of slaughterhouse‐derived cattle ovaries were placed in IVM with different antioxidants: quercetin (2 μM), cysteamine (100 μM), carnitine (0.5 mg/ml), vitamin C (50 μg/ml) or resveratrol (2 μM). Oocytes matured without any antioxidant supplementation were used as control. The oocytes were assessed for maturation rates and for ROS and GSH levels by fluorescence staining in 2′,7′‐dichlorodihydrofluorescein diacetate and Cell Tracker Blue, respectively. Embryo production was assessed in terms of cleavage, blastocysts and hatching rates and embryo cell numbers. The results expressed in arbitrary fluorescence units showed ROS reduction (p < .05) in the groups with quercetin (27.5 ± 3.4), vitamin C (27.1 ± 3.0) or resveratrol (28.1 ± 4.7), in comparison with those with cysteamine (34.9 ± 4.5), carnitine (34.6 ± 3.8) or to the control group (36.5 ± 5.2). GSH levels increased (p < .05) in cysteamine (63.5 ± 5.5) or carnitine (60.8 ± 4.4) groups in comparison with quercetin (52.7 ± 5.1), vitamin C (53.0 ± 3.8), resveratrol (53.1 ± 4.4) or to the control (49.6 ± 4.5). Nuclear maturation cleavage and hatched blastocysts rates did not differ (p > .05) between groups. However, blastocyst rates after in vitro fertilization in quercetin (53.5 ± 3.9%), vitamin C (52.1 ± 3.1%) resveratrol (54.2 ± 4.0%), cysteamine (52.4 ± 2.7%) or carnitine (54.2 ± 3.1%) groups were higher (p < .05) than in the control (47.2 ± 2.7%). Total cell numbers in embryos from the vitamin C, resveratrol, cysteamine or carnitine groups were higher than in quercetin and control groups, which were similar to each other. The results suggest that using antioxidants during IVM may reduce oxidative stress either by decreasing ROS levels directly or by increasing GSH levels in oocytes, depending on the type of antioxidant used. Overall, oxidative stress control during IVM with the antioxidants examined here improved blastocyst development with similar efficacy.     

Polymorphism of BMPR1B,BMP15 and GDF9 fecundity genes in prolific Garole sheep

Tropical Animal Health and Production - Mutation studies in different prolific sheep breeds have shown that the transforming growth factor beta super family ligands viz. the growth differentiation...