Showing papers in "Journal of Botany in 2015"
TL;DR: It is concluded that chlorophyll fluorescence measurements provide valuable physiological data; however, their use in agronomic studies for the prediction of agronomics traits should be done with some precaution.
Abstract: The impact of (long-term) drought acclimation and (short-term) heat stress and their combination on fast chlorophyll fluorescence induction curves (OJIP) and grain yield was tested using pot-grown plants of wild barley (Hordeum spontaneum) originating from Northern Egypt. Concerning agronomic traits, the main effect of drought was decreased biomass accumulation and grain yield, while heat specifically affected floral development. The treatments caused specific inhibitions of photosystem II (PSII) functionality. While heat stressed plants showed a reduction of maximum quantum efficiency of PSII (), an indication of effects on oxygen evolving complex (OEC) functionality, and the connectivity of PSII units, these features were entirely missing in drought acclimated plants. Drought caused a reduction of the Performance Index () and of the relative amplitude of the IP-phase of the OJIP induction curve (). Individuals suffering from a combination of drought and heat showed a better ability to recover photosynthetic electron transport after the relief of stress in comparison to heat stressed plants. However, this improved capacity to recover was not accompanied by an increased grain yield. Thus, we conclude that chlorophyll fluorescence measurements provide valuable physiological data; however, their use in agronomic studies for the prediction of agronomic traits should be done with some precaution.
66 citations
TL;DR: Due to the high polyphenolic content and antioxidant capacity of these plants and significant inhibitory effect of the plants on alpha-amylase, these plants can be proposed for treatment of diabetic patients.
Abstract: Postprandial hyperglycemia plays an important role in the development of type 2 diabetes. Inhibition of alpha-amylase was led to a delay in breaks down of starch and glycogen and prevented a rapid rise in blood sugar. Alpha-amylase was isolated by gel filtration chromatography Sephadex G-75 from bovine pancreas. Then, total methanolic extracts of plants were prepared and IC50 values of extracts on alpha-amylase were obtained and compared with acarbose IC50. The polyphenolic content of extracts and antioxidant capacity were determined by Folin-Ciocalteu test and DPPH test, respectively. The specific activity of alpha-amylase was 48.2 U/mg. For inhibition of alpha-amylase, IC50 values of H. persicum, Z. jujuba, and acarbose were 307, 827, and 113 μg/ml, respectively. For inhibition of DPPH radical, IC50 values of extracts were 235 and 701 μg/ml. Total phenolic contents of methanol extracts were and μg tannic acid equivalent/mg extract. Acarbose causes gastrointestinal symptoms and liver toxicity, but H. persicum and Z. jujuba decrease these side effects and prevent gastrointestinal disorders. Due to the high polyphenolic content and antioxidant capacity of these plants and significant inhibitory effect of the plants on alpha-amylase, these plants can be proposed for treatment of diabetic patients.
49 citations
TL;DR: The presence of IAA metabolizing enzymes and IAA production with PGPR traits including ACC deaminase activity of the symbionts was essential for plant microbe interaction and nodule function.
Abstract: Indole acetic acid is a phytohormone which plays a vital role in plant growth and development. The purpose of this study was to shed some light on the production of IAA in roots, nodules, and symbionts of an aquatic legume Neptunia oleracea and its possible role in nodular symbiosis. The symbiont (N37) was isolated from nodules of this plant and identified as Rhizobium undicola based on biochemical characteristics, 16S rDNA sequence homology, and DNA-DNA hybridization results. The root nodules were found to contain more IAA and tryptophan than root; however, no detectable amount of IAA was found in root. The IAA metabolizing enzymes IAA oxidase, IAA peroxidase (E.C.1.11.1.7), and polyphenol oxidase (E.C.1.14.18.1) were higher in root than nodule but total phenol and IAA content were reversed. The strain N37 was found to produce copious amount of IAA in YEM broth medium with tryptophan and reached its stationary phase at 20 h. An enrichment of the medium with mannitol, ammonium sulphate, B12, and 4-hydroxybenzaldehyde was found to promote the IAA production. The presence of IAA metabolizing enzymes and IAA production with PGPR traits including ACC deaminase activity of the symbionts was essential for plant microbe interaction and nodule function.
44 citations
TL;DR: The study confirmed that very few species had dominance and abundance, influence of altitude and slope on species distribution, and fair regeneration of the forest, and that Altitude and slope had significant effect on basal area and dominance.
Abstract: Our current study was conducted in Oda forest to explore floristic composition, vegetation structure, and regeneration of woody species in a newly established Humbo Carbon Project. In the project, the above information for sufficient conservation and management of the forest is not well documented. Data were collected in October and December 2014. Thirty-two quadrats (20 m × 20 m) lying 100 m far apart were used for shrub and tree data. In each major plot, subplots (1 m 2) were established at the center and corner for seedlings and saplings data. Altitude, slope, and aspect were measured using GPS and clinometers. DBH, basal area, and IVI were used for vegetation structure. Among 62 species confined in 32 families and 54 genera, Dodonaea angustifolia and Combretum molle were the densest and the most dominant and frequent species with higher IVI. Altitude and slope had significant effect ( ) on basal area and dominance. Bell and inverted J shaped patterns of selected woody species were identified. The seedling, sapling, and matured tree had 2.3%, 23.7%, and 74% density ha −1 of individuals, respectively. Generally, the study confirmed that very few species had dominance and abundance, influence of altitude and slope on species distribution, and fair regeneration of the forest.
29 citations
TL;DR: The study disclosed the scopes of clonal propagation Swietenia macrophylla through branch cutting treated with IBA and showed significant difference of rooted cuttings among the treatments, as well as difference of shoot number per cutting, the length of the longest shoot, and number of leaves per cutting among the treatment.
Abstract: The study discloses the scopes of clonal propagation Swietenia macrophylla through branch cutting treated with IBA. A total of four hundred cuttings were used with four replications to assess the rooting ability. The study exposed significant () difference of rooted cuttings among the treatments. The highest (62.51%) rooting percent was observed in cutting with 0.4% IBA treatment. In addition, root number and its length per cutting were increased with increasing IBA concentration (). The experiment showed significant () difference of sprouting among the treatments. The highest (67.27%) percent of sprouting was observed in cuttings with 0.4% solution, which showed a similar fashion of percent of rooting. The study also showed significant () difference of shoot number per cutting, the length of the longest shoot, and number of leaves per cutting among the treatments. The overall survival of rooted cuttings after transfer to polybag significantly () differed among the cuttings treated with different IBA solution. The highest survival percentage (69.67%) was observed in the cuttings rooted with 0.4% IBA treatment and the lowest (55.6%) survival was found in cuttings treated with control. The use of 0.4% IBA treatment is suggested for rooting of juvenile leafy branch cutting of S. macrophylla.
11 citations
TL;DR: The fate of integrated Ri T-DNA rol genes during regeneration via indirect somatic embryogenesis and stability of its effect on morphology and tylophorine content of Ri-transformed plants have been studied in Tylophora indica.
Abstract: The fate of integrated Ri T-DNA rol genes during regeneration via indirect somatic embryogenesis and stability of its effect on morphology and tylophorine content of Ri-transformed plants have been studied in Tylophora indica. Integration and expression of Ri T-DNA genes in transformed embryogenic callus lines derived from transformed root lines, 300 Ri-transformed somatic embryos, and 23 Ri-transformed plant lines were analysed. Fifty root lines studied showed integration and expression of four rol genes of TL-DNA. Spontaneous regeneration via indirect somatic embryogenesis was obtained from root lines that were TL
8 citations
TL;DR: Sea oxeye daisy Borrichia frutescens responds differently to clipping versus galling by A. borrichiae and better tolerates galling in terms of nonreproductive performance and survival, which suggests resource regulation of meristems by the midge.
Abstract: Although herbivory may result in plant death, the mode and timing of damage may produce variable wounding responses in the attacked plant. In this study, effects of different types of apical meristem damage on growth and performance of sea oxeye daisy Borrichia frutescens (L.) DC were compared. Damage involved either clipping or galling of the apical meristem by the gall midge Asphondylia borrichiae Rossi and Strong. Apical dominance was relatively weak before flowering and stronger in short ramets that were shaded by taller neighbors later in the season. Clipped ramets delayed sprouting new stems, and galled ramets sprouted new stems quickly compared to intact ramets, but final stem counts were similar across treatments. Clipping significantly delayed flowering, reduced seed head ripening time, and resulted in fewer seed heads and seeds. Galling did not significantly impact reproduction compared to intact ramets. Nitrogen supplementation significantly increased stem count and seed count and lengthened seed ripening time. Borrichia frutescens responds differently to clipping versus galling by A. borrichiae and better tolerates galling in terms of nonreproductive performance and survival. Galling from A. borrichiae likely prevents Borrichia frutescens from flowering, which suggests resource regulation of meristems by the midge.
8 citations
TL;DR: In vitro seed germination, embryo differentiation, and ex vitro seedling production from in vitro rhizome-like bodies of a terrestrial orchid, Eulophia promensis Lindl is described.
Abstract: This communication describes in vitro seed germination, embryo differentiation, and ex vitro seedling production from in vitro rhizome-like bodies of a terrestrial orchid, Eulophia promensis Lindl. Effects of two nutrient media, namely, Murashige and Skoog (MS) and Phytotechnology Orchid Seed Sowing medium (P723) supplemented with 6-benzylaminopurine (BAP; 0.5–1.0 mgL−1) and/or α-naphthalene acetic acid (NAA; 0.5–1.0 mgL−1) and activated charcoal (2.0 gL−1), were studied on seed germination and subsequent development of embryos. Maximum seed germination (100%) was recorded in P723 medium fortified with 1.0 mgL−1 BAP
8 citations
TL;DR: Results show that propagating trees of the species by air layering is possible and this technique can be used to multiply and keep this species, which will reduce the regeneration problem linked to a low seed germination rate.
Abstract: Prosopis africana is a species of great socioeconomic importance but threatened with extinction in Niger because of overuse and regeneration problem. This study, conducted in the Maradi (Niger) area, precisely at El Gueza in the south of Gazaoua department, aims to evaluate the vegetative propagation capacity of P. africana by air layering under the Sudano-Sahelian climate of the south-central Niger. A ring of bark was taken on each selected branch and the wound was covered with a black plastic filled with a damp mixture of soil and wood debris. The chosen parameters are the diameter class and the position on the branch. In all, 60 branches were treated and followed for 130 days: 28.33% produced shoots and there was no significant difference between the diameter classes and between the positions. These results show that propagating trees of the species by air layering is possible and this technique can be used to multiply and keep this species, which will reduce the regeneration problem linked to a low seed germination rate.
7 citations
TL;DR: Comparing theCarotenoid content in Trentepohlia abietina growing in different types of barks, sample from smooth bark had the highest amount of carotenoids both in summer and in winter, followed by the sample from rough bark, and lowest amount was noted in fissured bark.
Abstract: Trentepohlia Martius, a dominant green subaerial alga, grows abundantly in Shillong and imparts the yellow, red, and orange colours to most of the tree barks, walls, rocks, and electric poles because of high accumulation of carotenoids in their filaments. This study emphasised the seasonal changes in carotenoid content amongst four different species of Trentepohlia, that is, T. diffracta, T. arborum, T. umbrina, and T. abietina, collected from four different substrata, that is, wall, rock, electric pole, and three types of tree bark (smooth, fissured, and rough). Quantitative estimation of different carotenoids, namely, β-cryptoxanthin, lutein, and β-carotene, from HPLC chromatogram peak showed a significant seasonal variation in all of the four species and β-carotene was threefold more in winter compared to summer. Amongst the selected species, T. diffracta collected from wall contained the highest amount of β-carotene both in summer and in winter, followed by T. arborum from rock and T. abietina from bark, and least amount was in T. umbrina collected from electric pole. Comparing the carotenoid content in Trentepohlia abietina growing in different types of barks, sample from smooth bark had the highest amount of carotenoids both in summer and in winter, followed by the sample from rough bark, and lowest amount was noted in fissured bark.
6 citations
TL;DR: Lack of correlation between ammonium levels and survival of transgenic plants suggests that ammonium toxicity is not a main reason for the birch plant death after the PPT treatment.
Abstract: Transformation of plants with genes encoding a glutamine synthetase (GS), a key nitrogen metabolism enzyme, is usually used to increase productivity. However, overexpression of these genes may increase resistance to phosphinothricin (PPT) that irreversibly inhibits GS causing ammonium accumulation in plant tissues. Transgenic plants of two birch (Betula pubescens) genotypes expressing a pine cytosolic GS gene were used for studying the PPT effect on trees. Two control and 8 transgenic lines were treated with herbicide “Basta” at dose equivalent to 2.5 and 5 Lha−1. Necrosis and abscission of leaves occurred irrespective of a transgenic status or the treatment dose. Ammonium content in leaf tissue in 3 days after the 5 Lha−1 treatment was substantially increased in all plants, 3.2–16.0 times depending on line. After the 2.5 Lha−1 treatment, ammonium content in three transgenic lines was not different from that in control variant sprayed with water. The herbicide treatment caused more prominent desiccation in the bp3f1 genotype nontransgenic plants as compared to transgenic plants, but not in the bp4a genotype. Lack of correlation between ammonium levels and survival of transgenic plants suggests that ammonium toxicity is not a main reason for the birch plant death after the PPT treatment.
TL;DR: It is concluded that the CA and the physiological and morphological attributes work together, explaining the radial growth and increasing seedlings quality, which optimized efficient seedling production under full sun, in P. gigantocarpa and S. parahyba.
Abstract: Variations in light intensity can lead to important anatomical and morphophysiological changes in plants. Aiming to increase knowledge about the Amazonian tree species, this study examines the influence of shade on the cambial activity and development of Parkia gigantocarpa Ducke and Schizolobium parahyba var. amazonicum (Huber ex Ducke) Barneby seedlings. Seedlings of the two species were grown in a nursery under four shade intensities (treatments): full sun, low, moderate, and high shade (resp., 0%, 23%, 67%, and 73% of shade, or 2000, 1540, 660, and 540 µmol·m−2·s−1) obtained with polyethylene screens. We measured plant height, stem diameter, biomass production, stomatal conductance ( ), transpiration (E), photosynthesis (A), and cambial activity (CA) (xylem, cambium, and phloem). Also, we calculated the Dickson Quality Index (DQI). The highest values of biomass production, , E, A, and DQI, were found under full sun, in P. gigantocarpa, and under low shade intensity in S. parahyba. In both species high shade intensity reduced CA. We concluded that the CA and the physiological and morphological attributes work together, explaining the radial growth and increasing seedlings quality, which optimized efficient seedling production under full sun, in P. gigantocarpa, and under low shade intensity in S. parahyba.
TL;DR: The results showed that more than half of invasive alien shrubs in Rwanda were introduced as ornamentals, and species introduced for purposes other than food or culinary use showed higher likelihood of becoming invasive.
Abstract: The introduced shrub flora in Rwanda was analyzed and the risk of invasion was assessed based on the species’ purposes of introduction. The results showed that more than half of invasive alien shrubs in Rwanda were introduced as ornamentals. They include Agave americana L., Bryophyllum proliferum Bowie ex Hook., Caesalpinia decapetala (Roth) Alston, Lantana camara L., and Tithonia diversifolia (Hemsley) A. Gray. However, these represented only 3.16% of the total number of introduced ornamental shrubs. At the time when the study was conducted, no introduced food crop had become invasive. Species introduced for purposes other than food or culinary use showed higher likelihood of becoming invasive.