(Press-News.org) Collective research to date regarding nutrients found in the leaves of contemporary cycad species has been inconsistent as far as data collection and narrow in scope, according to a University of Guam-led literature review published on Nov. 19 in Horticulturae journal.
Understanding nutrient accumulation within cycads is essential to effective horticultural management, and more importantly, conservation of this plant group, which is highly prized within the horticulture trade and also threatened worldwide.
"Cycads comprise the most threatened group of plants worldwide, but they are also one of the least studied plant groups," said Benjamin Deloso, a cycad specialist with the University of Guam and lead author of the study. "Most of the disciplines of cycad research are only now accumulating enough peer-reviewed literature to enable organized global reviews, such as this one."
The effort to compile and summarize peer-reviewed literature on the subject was undertaken by scientists from Guam, Florida, the Philippines, Thailand, and the Micronesian Island of Yap -- each of whom also co-authored some of the articles cited in the review.
They concluded that in order to draw more reliable comparisons among studies of cycad leaf nutrition, future research should include:
More taxa
The literature reviewed represented only 13% of the world's cycad species. More species need to be added to the published database to increase relevance of the results.
More plants in their natural habitats
The number of cycad species from which native habitat data were obtained was an unusually low 4% of the 358 described species. Most of the reviewed publications reported data from botanic garden settings, which have been shown to artificially change the concentration of cycad leaf nutrients.
The influence of season
In the few studies that factored in the season, the results found that leaf nutrients varied among male and female plants and plants of different provenances, indicating future research should take season into account.
The influence of insect herbivory
Many cycad taxa co-evolved with leaf-eating insects, while others are threatened by non-native pests, yet only one study in the review factored in and noted the influence of insect herbivory on cycad leaf nutrients.
The influence of biotic and abiotic factors
Perhaps the greatest benefit of the review was the explanation of biotic and abiotic factors that have been shown to influence cycad leaf nutrient relations. Future studies can now be designed to ensure research methods include measurements of plant size, leaf age, level of shade, position of leaflets within the compound leaf, and the concentrations of nutrients within the soils of the root zone -- all factors that influence leaf nutrient concentrations.
Furthermore, the sampling and analytical methods were highly disparate among the studies.
"One of our main points was that the protocols for sampling leaf tissue to determine nutrient concentrations of cycad leaves have not been homogeneous among the various research agendas," Deloso said. "This compromised our ability to unequivocally determine any canonical trends in the results."
Discoveries based on data review
Despite the disparities in research methods, the review of published research revealed that cycad leaf nitrogen and phosphorus concentrations exceeded the global mean for these elements in all seed-bearing plants. According to the authors, the cyanobacteria endosymbionts that inhabit cycad roots provide additional nitrogen for the cycad to exploit. These cyanobacterial endosymbionts are absent from many other plant groups, which may help explain these findings.
Deloso said the findings of this first-ever literature review on the topic of leaf nutrition in cycads are key moving forward with cycad research.
"Among my co-authors were the world's three leading authorities for Guam's native cycad, Cycas micronesica. This tree is one of the many endangered cycad species, and these experts are crucial sources of knowledge to inform future conservation decisions," he said.
INFORMATION:
Even at the start of the COVID-19 pandemic last year, people around the world became more fearful of what could happen to them or their family.
A new Flinders University study of 1040 online participants from five western countries published in PLOS ONE explores people's response to the stresses of the escalating pandemic, finding more than 13% of the sample had post-traumatic stress disorder (PTSD) related symptoms consistent with levels necessary to qualify for a clinical diagnosis.
With ongoing economic and social fallout, and death toll of more than 2 million, the team of psychology researchers warn more needs to be done to cope with ...
AURORA, Colo. (Jan. 22, 2021) - Researchers at the University of Colorado Anschutz Medical Campus have discovered a direct association between placental function in pregnant women and future metabolic disorders in children and adults, a finding that could lead to earlier intervention and diagnosis of disease.
"We've known for some time that many major diseases in adults like diabetes and cardiovascular disease are at least partly caused by problems during fetal life," said the study's senior author Thomas Jansson, MD, PhD, professor of Obstetrics & Gynecology ...
Our state of consciousness changes significantly during stages of deep sleep, just as it does in a coma or under general anesthesia. Scientists have long believed - but couldn't be certain - that brain activity declines when we sleep. Most research on sleep is conducted using electroencephalography (EEG), a method that entails measuring brain activity through electrodes placed along a patient's scalp. However, Anjali Tarun, a doctoral assistant at EPFL's Medical Image Processing Laboratory within the School of Engineering, decided to investigate brain activity during sleep using magnetic resonance ...
In a promising result for the success of vaccines against COVID-19, rhesus macaque monkeys infected with the human coronavirus SARS-CoV-2 developed protective immune responses that might be reproduced with a vaccine. The work was carried out at the California National Primate Research Center at the University of California, Davis and is published Jan. 22 in the journal Nature Communications.
"These results suggest that vaccines inducing durable protective immunity against SARS-CoV-2 do so by stimulating robust germinal center responses - a question that can be effectively answered ...
Scientists from the International Centre for Radio Astronomy Research (ICRAR) and The University of Western Australia (UWA) have set a world record for the most stable transmission of a laser signal through the atmosphere.
In a study published today in the journal Nature Communications, Australian researchers teamed up with researchers from the French National Centre for Space Studies (CNES) and the French metrology lab Systèmes de Référence Temps-Espace (SYRTE) at Paris Observatory.
The team set the world record for the most stable laser transmission by combining the Aussies' 'phase stabilisation' technology with advanced self-guiding optical ...
New research has found that growing up in a bilingual home can provide unexpected cognitive benefits later in life.
The study, published in the journal Scientific Reports, demonstrates for the first time that adults who acquired their second language as a young child (early bilinguals) are quicker at shifting attention and quicker at detecting visual changes compared to adults who learnt their second language later in life (late bilinguals).
Led by Dr Dean D'Souza of Anglia Ruskin University (ARU), the research saw 127 adults take part in two separate ...
There is a saying that you can't teach old dogs new tricks. When it comes to canine behavioral problems, age is only one factor that can predict how well a pet may respond to clinical intervention. In a paper published in Frontiers in Veterinary Science, researchers provide the first evidence on the importance of not just a dog's age, sex and size on treatment success, but the owner's personality and the kind of bond that human and animal share.
The study analyzed the physiological and psychological characteristics of 131 dog-owner pairs who attended a veterinary behavioral service over a six-month period. The statistical results were based on a behavioral assessment questionnaire that was given at the beginning, middle and end of the ...
A new collaborative study led by researchers at the National Institute for Environmental Studies, the University of Tokyo, and Michigan State University exposes the role of dams for mitigating flood risk under climate change.
Flood is amongst the costliest natural disasters. Globally, flood risk is projected to increase in the future, driven by climate change and population growth. The role of dams in flood mitigation, previously unaccounted for, was found to decrease by approximately 15% the number of people globally exposed to historical once-in-100-year ...
Questions about why such affluent western societies are facing a reversal in life expectancy are sounding loud alarm bells for Professor Fran Baum, Matthew Flinders Distinguished Professor and Director of the Southgate Institute for Health, Society and Equity.
Professor Baum is lead author of a study that offers a new perspective on why women live longer than men - noting with concern that while women live longer, many of the recognised social determinants of health are worse for women than men.
The study serves an important reminder of why policy makers need to receive more carefully nuanced research that drills into specific gender data that can best inform public health policy initiatives.
"We need gendered analysis to shape ...
During a pandemic, decisions have to be made under time pressure and amid scientific uncertainty, with potential disagreements among experts and models. With COVID-19, especially during the first wave, there was uncertainty about the virus transmissibility, the disease severity, the future evolution of the pandemic and the effectiveness of the proposed policy interventions, such as wearing face masks or closing schools. Together with a group of epidemiologists and economists, including the Nobel Prize winner Lars Peter Hansen, Bocconi professors Massimo Marinacci, AXA-Bocconi Chair in Risk, and Valentina Bosetti investigated how modern decision theory can help policymakers ...
