572 research outputs found
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Role of endophytes in early seedling growth of plants: a test using systemic fungicide seed treatment
No full textSystemic fungicide seed treatments are routinely used in conventional agriculture to control soil and seedborne
diseases, but little is known about their unintended
adverse effects on non-target beneficial fungal endophytes that are known to be involved in plant growth and development. This study evaluated the seed treatment effect of a broad spectrum systemic fungicide, carbendazim (bavistin) on symbiotic association of fungal endophytes in rice and on early seedling growth of rice, green gram, soybean, and cowpea. Seeds were surface sterilized with sodium hypochlorite followed by 0.2% bavistin treatment. Growth of fungal endophytes was significantly affected by the seed treatment with fungicide in rice seedlings, while shoot and root growth was suppressed in all the crops. Quantitative real time PCR showed that the level of expression of two basal transcriptional regulator genes, OsBTF3 and OsNFYC1
that are required for seed germination and seedling
growth significantly decreased in bavistin treated rice
seedlings. Re-inoculation of consortia of fungal endophytes onto bavistin treated rice seedlings significantly recovered seedling growth and development. These results suggest that fungicide treatment of seeds affects early seedling growth and has negative impact on beneficial fungal endophytes that are involved in plant growth and development. This study provides information on possible ill effects of fungicide on beneficial fungal endophytes that play key roles in early seedling growth of plants and also open up the prospect to additional research on different crops in vitro and field conditions to determine the consequences of fungicide effects and optimise fungicide application strategies to develop sustainable disease control methods
Sequestration of the plant secondary metabolite, colchicine, by the noctuid moth Polytela gloriosae (Fab.)
No full textColchicine, a well-known alkaloid, is a potent inhibitor of polymerization of tubulin leading to mitotic arrest. It is highly toxic to eukaryotic cells but also widely used in the field of medicine and plant breeding. Gloriosa superba (family: Colchicaceae) is an important natural source of colchicine. The seeds, tubers and leaves of this plant contain about 0.8, 1.2 and 0.014%
colchicine by dry weight respectively. A noctuid moth, Polytela gloriosae (family: Noctuidae), feeds voraciously on leaves of G. superba without any adverse effect. However, the fate of colchicine and the mechanisms by which the insect is able to overcome the toxicity of the metabolite is not known. Here, we trace the fate of colchicine in both, the larva and moth of P. gloriosae. Colchicine was quantified in different body parts of the larvae and moth by high performance liquid chromatography, liquid chromatography mass spectrophotometry and nuclear magnetic resonance methods. Of the total colchicine taken in by the larva, a larger portion was excreted, while the rest was sequestered in its cuticle. In the moths however, the wings, legs
and antennae were found to accumulate high amount of colchicine. The sequestered colchicine, in both the larva and adult, were chemically identical to that found in the plant. Negligible amounts of demethyl-(−)-colchicine, a less toxic derivative of colchicine was also detected. We discuss the probable adaptive significance of sequestration of colchicine by the insect
Exploring DNA quantity and quality from raw materials to botanical extracts
Full text linkObjectives: The aim of this study was to explore the variability in DNA quality and quantity along a gradient of industrial processing of botanical ingredients from raw materials to extracts.
Methods: A data matrix was assembled for 1242 botanical ingredient samples along a gradient of industrial
processing commonly used in the Natural Health Product (NHP) industry. Multivariate statistics was used to
explore dependant variables for quality and quantity. The success of attaining a positive DNA test result along a
gradient of industrial processing was compared among four biotechnologies: DNA barcoding, NGS, Sanger
sequencing and qPCR.
Results: There was considerable variance in DNA quality and quantity among the samples, which could be
interpreted along a gradient from raw materials with greater quantities (50–120 ng/μL) of DNA and longer DNA
(400-500bp) sequences to extracts, which were characterized by lower quantities (0.1–10.0 ng/μL) and short fragments (50-150bp).
Conclusions: Targeted molecular diagnostic tests for species identity can be used in the NHP industry for raw and processed samples. Non-targeted tests or the use of NGS for any identity test needs considerable research and
development and must be validated before it can be used in commercial operations as these methods are subject
to considerable risk of false negative and positive results. Proper use of these tools can be used to ensure
ingredient authenticity, and to avert adulteration, and contamination with plants that are a health concern. Lastly these tools can be used to prevent the exploitation of rare herbal species and the harvesting of native biodiversity for commercial purposes
Assessing the Impacts of Landscape Change and Habitat Degradation on Mammal Diversity and Distribution in the Northern Eastern Ghats, Andhra Pradesh, Using Ecological, Geographic and Social Information
No full textLandscape structure in forest landscapes strongly determines ecosystems functioning, ecological processes and species persistance. Anthropogenic activities are leading to landscape modification, causing habitat degradation and disruption of ecological processes, resulting in biodiversity loss. Mammals in particular have experienced major declines in their populations and ranges globally and across India, largely owing to human induced landscape changes and habitat degradation. As forest landscapes continue to shrink globally, the impacts of habitat loss and degradation on mammals outside protected areas, and the importance of protected areas in sustaining mammals at a landscape level needs to be examined in finer detail to facilitate their conservation
How and why do endophytes produce plant secondary metabolites?
No full textDespite numerous studies reporting endophytic fungal production of metabolites chemically similar to the secondary metabolites produced by their host plants, how and why the fungi produce these metabolites remain largely unknown. Here, we review the literature on endophytic fungal production of taxol and camptothecin, two extensively studied plant secondary metabolites, and
highlight critical gaps in our knowledge that need to be addressed to adequately answer the above questions. We show that detailed studies are required for conclusive demonstration of i) the production of these metabolites by the fungi, ii) the tolerance of the fungi to the produced cytotoxic metabolites, and iii) the adaptive significance of the metabolite production to the fungi.
Although our focus is on two widely studied plant secondary metabolites produced by fungi, the questions addressed here are equally applicable to the production of a large number of other fungal metabolites that are similar to those produced by their host plants
Adapting or Chasing Water? Crop Choice and Farmers' Responses to Water Stress in Peri‐Urban Bangalore, India
No full textUnregulated groundwater extraction has led to declining groundwater tables and increasing water scarcity in the Indian subcontinent.
Understanding how farmers respond to this scarcity is important from multiple perspectives—equity in access, livelihood
security and resource sustainability. We present a case from the rapidly urbanizing Arkavathy sub-basin near
Bangalore city in southern India where irrigation is fully groundwater dependent. Using cross-sectional data from a stratified
random sample of 333 farmers from 15 villages, we investigated the factors that determine their choice of crops under conditions
of water scarcity and urbanization. Binary logit analysis showed that farmers with a large landholding respond by tapping
deep groundwater using borewells. Multinomial logit analysis revealed that access to groundwater, variation in the proximity to
the product market (city) and labour availability influence crop choice decisions. We observe that current responses indicate
what has been characterized in the literature as chasing strategies. These largely favour well-off farmers and hence are inequitable.
While the choice of water-intensive crops and unregulated pumping have aggravated water stress, the uptake of watersaving
technologies among irrigated farmers has been low, showing that resource sustainability may not be a concern where
non-farm diversification opportunities exist
Invasion compounds an ecosystem-wide loss to afforestation in the tropical grasslands of the Shola Sky Islands
No full textTropical montane habitats, including the Shola Sky Islands in the Western Ghats, host several threatened taxa of which, the global distributions are restricted to these mountain-tops. The rapidly increasing human footprint and the spread of invasive alien plants have already resulted in the local extinction of several taxa. Here we examine the entire Shola Sky Islands ecosystem to estimate the extent of habitat loss and to create a baseline of land use in this rapidly changing landscape. We used LANDSAT imageries from 1973, 1995 and 2017, with 840 ground
truth points across the ecosystem. We find substantial landscape modification in the large high elevation plateaus (7–60%) over the last four decades while changes are muted in the other parts. The loss of grasslands to
exotic trees predominates (340 km2, 23%) the modification of this landscape, and, continues today at a rapid
pace. Contrary to popular belief, Shola Forests have been relatively stable, implying that most plantations were
established on grasslands—traditionally classified as “unproductive wastelands”. Across the Protected Area (PA)
network, Reserve Forests (RF), the least protected areas have faced the greatest loss of grasslands. Older PAs
have lost relatively fewer grasslands, but the invasion from adjoining RFs is now increasing. We highlight the
complexity of conservation in this landscape with three case studies of PAs with different management histories.
Our study highlights the rapid loss of native Shola Grasslands, the continuing loss to invasive exotic trees, and the challenges of conserving this critical habitat with traditional modes of conservation
Origin and evolution of the genus Piper in Peninsular India
No full textThe evolution of Peninsular Indian biodiversity has been a fascinating topic of research due to historical connections of this region to the ancient Gondwanaland. We investigated the phylogeny and historical biogeography
of nearly all extant species of the genus Piper reported from the region to assess the biogeographical origins and
test mechanisms of lineage diversification (dispersal, vicariance and in situ radiation) of this highly diverse genus of angiosperms commonly found in the understory of evergreen forests. The phylogeny of 21 species of Piper
reported from Peninsular India was reconstructed for the first time, which included three new putative species
from the Western Ghats. We used BEAST for the divergence time estimations (using three constraints), and ancestral range estimations were performed with the dated phylogenetic tree using BIOGEOBEARS. Divergence dating analysis revealed that the genus Piper originated during lower Cretaceous around 110 Ma [95% highest posterior density (HPD): 116–105 Ma] and colonized Peninsular India five times independently, from Southeast Asia starting from the Oligocene. The two major dispersals into India occurred during the periods of 27.3 Ma (95% HPD: 35.8–19.9.) and 15.5 Ma (95% HPD: 24.9–7.11). This was followed by rapid radiations in some lineages with subsequent back dispersals to Southeast Asia. Our study indicates that dispersals from Southeast Asia led to the arrival of Piper to Indian subcontinent following the Indo-Eurasian collision. Members of Piper have colonized and diversified within the climatically stable habitats of Peninsular India. Furthermore, the present study provides evidence for the Miocene overland dispersal of Piper species to Africa from South Asia
Influence of phylogeny and abiotic factors varies across early and late reproductive phenology of Himalayan Rhododendrons
Full text linkUnderstanding the influence of evolutionary history on species-specific phenological events of high-altitude plants and their sensitivity to the abiotic factors has gained importance mainly in the context of climate change. However, the majority of phenology studies across altitudinal gradient are carried out on flowering, whereas other reproductive phenology events are seldom considered. We tested the role of abiotic factors and evolutionary history on the reproductive phenology traits of high-altitude Rhododendron community which comprised of 10 locally aggregated species in Kyongnosla Alpine Sanctuary, Sikkim Himalaya. The study was carried out from 2013 to 2015 across an altitude gradient of 3400–4230 m a.s.l. We generated dated phylogenetic hypotheses to test for phylogenetic signal in reproductive phenology
events, and its durations across 10 Rhododendron species and also among groups of species distributed at every 100 m altitude. Comparative phylogenetic methods were used to explore the relationship between phenology traits and abiotic variables such as daylength and temperature. The early phenology events such as budding, flowering, and initial fruiting, which occurred during the favorable month of the year, exhibited strong phylogenetic signal and were mainly associated with daylength and temperature. In contrast, the later events such as immature fruiting, mature fruiting, and fruit dehiscence, which occurred during the later months of the year, showed a weak phylogenetic signal and were mostly associated
with daylength. With the increase in altitude, we found a decreasing trend of phylogenetic signal for the early phenology events and later events did not show a significant trend. Our results suggest that only
early events are constrained by evolutionary history; thus, the closely related species share the similar timing of the early phenology events. Also, the role of shared evolutionary history in phenological trait sensitivity to the abiotic factors reduces from early to the late phenology events. This approach can be extended to other representative plant families of the Himalayan region to better understand the response of reproductive traits to abiotic factors in deep evolutionary time
Mainstreaming human and large carnivore coexistence through institutional collaboration
No full textAchieving coexistence between large carnivores and humans in human-dominated landscapes (HDLs) is a key challenge for societies globally. This challenge cannot be adequately met with the current sectoral approaches to HDL governance and an academic community largely dominated by disciplinary sectors. Academia (universities and other research institutions and organizations) should take a more active role in embracing societal challenges around conservation of large carnivores in HDLs by facilitating crosssectoral cooperation to mainstream coexistence of humans and large carnivores. Drawing on lessons from populated regions of Europe, Asia, and South America with substantial densities of large carnivores, we suggest academia should better embrace the principles and methods of sustainability sciences and create
institutional spaces for the implementation of transdisciplinary curricula and projects; reflect on research approaches (i.e., disciplinary, interdisciplinary, or transdisciplinary) they apply and how their outcomes could aid leveraging institutional transformations for mainstreaming; and engage with various institutions and stakeholder groups to create novel institutional structures that can respond to multiple challenges of HDL management and human–large carnivore coexistence. Success in mainstreaming this coexistence in HDL will rest on the ability to think and act cooperatively. Such a conservation achievement, if realized, stands to have far-reaching benefits for people and biodiversity