SPOROBOLUS SPICATUS, A POTENTIAL TURF GRASS UNDER THE CLIMATIC CONDITIONS OF UAE

Different accessions of Sporobolus spicatus were tested for the possible use in the landscaping sector of United Arab Emirates. In this regards, fifty accessions of S. spicatus were screened against five salinity levels of 15, 30, 45, 60 and 75dSm-1 at 3cm mowing height. Significant variations were found among the treatment for various characters of leaf colour, fresh and dry weight. Most of the accessions of the grass tolerated up to 45 dSm-1, without compromising on quality. Further increase in salinity, most of the accessions ceased to grow, except a few accessions which survived even at salinity levels of 75dSm-1. Many of the grasses exhibit better performance than Paspalam vaginatum, the prevailing commercial turf grass in UAE (used as control in this instance). As a whole accessions 45S, 18S, 35S and 37S showed salinity tolerance at 3cm mowing height and maintaining quality up to the acceptable level. Based on their tolerance to salinity and better performance, these accessions are recommended for turf use in public landscaping

Light quality and temperature effects on antirrhinum growth and development

An experiment was carried out to examine the effects of light quality on the growth and development of antirrhinum under three different temperatures 19 °C, 24 °C and 27 °C in glasshouses. Five different colour filters (i.e. ‘Red absorbing’, ‘Blue absorbing’, ‘Blue and Red absorbing’ and two ‘partially Blue absorbing’ materials) were tested, with one clear polythene as a control. Plant height, internode length and leaf area were significantly affected by the spectral filters as well as the temperature. Analysis of color filter’s effect on presumed photoreceptors to exist indicated that antirrhinum plant height was regulated by the action of a blue acting photoreceptor (BAP) and not the phytochrome. There was no evidence for an effect of phytochrome or BAP on time to flowering, however, increasing temperature levels effectively decreased the time to flowering. To predict the effects of different spectral qualities and temperature, simple models were created from data on plant height, internode length and time to flowering. These models were then applied to simulate the potential benefits of spectral filters and temperature in manipulation of growth control and flowering in antirrhinum

Performance of Exotic Tulip Cultivars under Agro-Climatic Conditions of Peshawar

The performance of ten exotic tulip cultivars under agro-climatic conditions of Peshawar was studied at Ornamental Nursery, Department of Horticulture, The University of Agriculture Peshawar, Pakistan during the year 2013-14. The experiment was laid out in Randomized Complete Block (RCB) Design with three replications. Ten cultivars of tulips viz., Bastogne, Don Quichotte, China Town, White Dream, Red Riding Hood, Mascotte, Orange Angelique, Strong Gold, Rajka and Romantic Sunset were tested for their performance. Significant differences (P≤0.05) were observed among the cultivars regarding various parameters. The cultivar “Don Quichotte” produced the maximum number of leaves per plant (8.1), bulbs per plant (6.3), as well as early flowering (144.3 days) that was statistically at par with cultivar “Strong Gold” for flowering (144.8 days), leaves per plant (7.3) and number of bulbs plant-1 (5.3). The maximum flower diameter (8.3 cm), bulb diameter (3.6 cm) and bulb weight (16.3 g) was noted in cultivar “Orange Angelique”. In the case of plant height, the tallest (32.5 cm) plants were observed in cultivar “White Dream”. The instant results suggest that Cultivar “Don Quichotte” is recommended for quality flowers and bulbs production under the agro-climatic conditions of Peshawar

Integrated effect of allelochemicals and herbicides on weed suppression and soil microbial activity in wheat (Triticum aestivum L.)

To evaluate the allelopathic effects of major crops and weeds, studies were conducted during 2011–12 and 2012–13 by utilizing water extracts of allelopathic plants namely rice (Oryza sativa L.), Parthenium hysterophorus L., Phragmites australis Cav., and Datura alba L. with reduced rates of fenoxaprop-p-ethyl and bromoxynil plus MCPA to control weeds. Application of Phragmites australis and Parthenium hysterophorus along with lower rates of fenoxaprop-p-ethyl and bromoxynil plus MCPA showed promising results by controlling weeds and improving yield. Parthenium hysterophorus extract with half of the recommended dose of fenoxaprop-p-ethyl and bromoxynil plus MCPA reduced weed density by 51 and 50% during year 1 and year 2, respectively, compared with the control. Phragmites australis extract with half of the recommended dose of fenoxaprop-p-ethyl produced grain yield (5.7 and 6.1\ua0t\ua0ha during year 1 and 2, respectively) in wheat. However, these results were also at par with Parthenium hysterophorus and Datura alba extracts in combinations with half the recommended doses of the above mentioned herbicides. The study of microbial activity showed higher amount of mineralizable carbon in D. alba with half the recommended dose of fenoxaprop-p-ethyl treated plots (0.073\ua0g during both the years). The lowest amount of mineralizable carbon (0.035 and 0.030\ua0g during year 1 and 2, respectively) was observed in the control plots. The presence of allelopathic plants in field crops and subsequent mixing in soil by tillage may create problems in crop production. Therefore, further studies are suggested to fully explore all the possible interactions among allelochemicals and herbicides

Heat Shock Proteins: Dynamic Biomolecules to Counter Plant Biotic and Abiotic Stresses

Due to the present scenario of climate change, plants have to evolve strategies to survive and perform under a plethora of biotic and abiotic stresses, which restrict plant productivity. Maintenance of plant protein functional conformation and preventing non-native proteins from aggregation, which leads to metabolic disruption, are of prime importance. Plant heat shock proteins (HSPs), as chaperones, play a pivotal role in conferring biotic and abiotic stress tolerance. Moreover, HSP also enhances membrane stability and detoxifies the reactive oxygen species (ROS) by positively regulating the antioxidant enzymes system. Additionally, it uses ROS as a signal to molecules to induce HSP production. HSP also enhances plant immunity by the accumulation and stability of pathogenesis-related (PR) proteins under various biotic stresses. Thus, to unravel the entire plant defense system, the role of HSPs are discussed with a special focus on plant response to biotic and abiotic stresses, which will be helpful in the development of stress tolerance in plant crops

Melatonin Mitigates the Infection of Colletotrichum gloeosporioides via Modulation of the Chitinase Gene and Antioxidant Activity in Capsicum annuum L.

Anthracnose, caused by Colletotrichum gloeosporioides, is one of the most damaging pepper (Capsicum annum L.) disease. Melatonin induces transcription of defense-related genes that enhance resistance to pathogens and mediate physiological activities in plants. To study whether the melatonin-mediated pathogen resistance is associated with chitinase gene (CaChiIII2), pepper plants and Arabidopsis seeds were treated with melatonin, then CaChiIII2 activation, hydrogen peroxide (H2O2) levels, and antioxidant enzymes activity during plant–pathogen interactions were investigated. Melatonin pretreatment uncoupled the knockdown of CaChiIII2 and transiently activated its expression level in both control and CaChiIII2-silenced pepper plants and enhanced plant resistance. Suppression of CaChiIII2 in pepper plants showed a significant decreased in the induction of defense-related genes and resistance to pathogens compared with control plants. Moreover, melatonin efficiently enabled plants to maintain intracellular H2O2 concentrations at steady-state levels and enhanced the activities of antioxidant enzymes, which possibly improved disease resistance. The activation of the chitinase gene CaChiIII2 in transgenic Arabidopsis lines was elevated under C. gloeosporioides infection and exhibited resistance through decreasing H2O2 biosynthesis and maintaining H2O2 at a steady-state level. Whereas melatonin primed CaChiIII2-overexpressed (OE) and wild-type (WT) Arabidopsis seedlings displayed a remarkable increase in root-length compared to the unprimed WT plants. Using an array of CaChiIII2 knockdown and OE, we found that melatonin efficiently induced CaChiIII2 and other pathogenesis-related genes expressions, responsible for the innate immunity response of pepper against anthracnose disease