Effects of submergence and de-submergence on a clonal plant

Effects of submergence and de-submergence on a clonal plant

Effects of submergence and de-submergence on a clonal plant

Submergence and de-submergence are common phenomena encountered by riparian plants as water levels fluctuate, but little is known about the role of physiological integration in the adaptation of clonal plants to such conditions. Luo et al. study Alternanthera philoxeroides (alligator weed) after 30 days of submergence and find that connections between submerged and non-submerged ramets enhance the performance of the submerged ramets, but little effect remains once the ramets have then been de-submerged for 20 days. This is due to quick recovery of growth and photosynthesis, and this combines with the benefits of physiological integration in allowing riparian clonal plants to survive submergence and spread rapidly after de-submergence.

For they are jolly good fellows

The Royal Society/Wikimedia Commons.

The Royal Society/Wikimedia Commons.

We’d like to add our words of congratulations to two recently appointed plant-biological Fellows of the Royal Society (of London for Improving Natural Knowledge), Professor Liam Dolan FRS (Sherardian Professor of Botany, Department of Plant Sciences, University of Oxford, UK) and Professor David Beerling FRS (Professor of Palaeoclimatology, Department of Animal and Plant Sciences, University of Sheffield, UK). Fittingly, Dolan has been so honoured because his ‘pivotal discoveries illuminate our understanding of the interrelationships between the development of plants, their evolution and the Earth System’ (e.g. Victor Jones and Liam Dolan, 2012Timothy Lenton et al.,  2012). Beerling has received his accolade in view of how ‘his integration of ecosystem processes into a broad geosciences framework established the importance of the terrestrial biosphere in Earth’s climate history’ (e.g. Laura Llorens et al., 2009*; Beerling, 2012). In addition to their research activities both have also taken time out to help spread the botanical message and enthuse the next generation of plant biologists, Dolan in the highly regarded undergraduate textbook Plant Biology, and Beerling with The Emerald Planet. Dolan and Beerling join approximately 1600 other Fellows in the self-governing fellowship that is the Royal Society, and which includes ‘many of the world’s most distinguished scientists drawn from all areas of science, engineering, and medicine’. Well done to these most deserving botanists!

 

* It’s also rather gratifying to think that having their work published in the Annals of Botany will have helped both gentlemen attain fellowship!

[And congratulations, too, to those UK researchers working in plant sciences (including fungi…) who’ve been named in the global Top 1%. This listing of ‘Highly Cited Researchers 2014’ names more than 3000 people selected by having writing the greatest numbers of ‘reports officially designated by Essential Science IndicatorsSM as Highly Cited Papers’. I counted four female and 11 male notables from addresses – ‘primary affiliations’ – in north, central, west and south of England, but none from Scotland (or Wales or Northern Ireland). However, I am intrigued by included scientist ‘Philip J. White’, whose primary affiliation is shown as King Saud University, Saudi Arabia (KSU), because I found no mention of this notable person on KSU’s website. So, I wonder if this could actually be the Philip J. White currently at The James Hutton Institute (Invergowrie, Scotland, UK). That P. J. White has many other affiliations – Special Professor in Plant Ion Transport at the University of Nottingham (UK), Adjunct Professor at the University of Western Australia, Visiting Associate Professor at the Comenius University, Bratislava (Slovakia), Visiting Professor of the Brazilian Research Council, and an Honorary Lecturer at the University of Dundee (Scotland) – so maybe KSU was amongst those at the time the census was taken? Or perhaps there’s been a mistake? Or there’s another Philip J. White who is even more highly cited than James Hutton’s? So, will P. J. White please get in touch and put the record straight? – Ed.]

[Ed. – we are pleased to be able to report that the mystery has now been solved. The PJ White referred to is indeed Philip White of the James Hutton Institute who is also a Professor in Biology at the King Saud University. And we are more than happy to advise that the same PJ White is a co-author on one of the Annals of Botany’s most highly downloaded papers – White PJ and Broadley MR, Calcium in plants; Annals of Botany 92: 487-511, 2003.].

Early wound reactions of Japanese maple during winter dormancy: the effect of two contrasting temperature regimes

14082-TDuring winter dormancy, temperate trees are capable of only a restricted response to wounding. Depending on the ambient temperature during winter dormancy, wounded trees may start compartmentalization, e.g. by producing inhibitory compounds, but it is thought that processes involving cell proliferation, such as the formation of callus and wound xylem, are delayed until the next growing season. In a recent study published in AoB PLANTS, Copini et al. investigated the effect of wounding on Acer palmatum trees during winter-bud dormancy and found that in the cold (4 °C) treatment, wound reactions were virtually absent. In the warm (15 °C) treatment, however, trees reacted actively to wounding within a three-week period by, e.g., forming callus and local wound xylem. They conclude that temperature is an important factor in wound reactions during winter dormancy and may even induce the formation of callus and wound xylem within a three-week period.

Variations in apomixis in diploid Paspalum rufum

Variations in apomixis in diploid <i>Paspalum rufum</i>

Variations in apomixis in diploid Paspalum rufum

The genus Paspalum (Poaceae) is a model to study gametophytic apomixis and its strong relation with polyploidy. Delgado et al. analyse the reproductive behaviour of natural diploid individuals of P. rufum and find that under self-pollination induction three genotypes develop seeds from both meiotic and aposporous embryo sacs, and one of them is able to complete the apomictic pathway. Cytoembryological observations reveal that all genotypes form aposporous embryo sacs, suggesting that apospory and parthenogenesis might be uncoupled. These results demonstrate variation in the functionality of apomixis components and also that genetic determinants of apomixis are not sufficient for an appreciable expression of the trait at the diploid level.

Can intensification be sustainable?

Contemporary interest in agricultural sustainability can be traced to environmental concerns that began to appear in the 1950s and 1960s. However, concepts and practices about sustainability date back at least to the oldest surviving texts from China, India, Greece and Rome. Today the global challenge is great.

In order to provide sufficient food for growing populations and their changing consumption patterns, some indicate that agriculture will have to expand into non-agricultural lands. However, the competition for land from other human activities makes this a costly solution, particularly if protecting biodiversity and the public goods provided by natural ecosystems (e.g. carbon storage in forests) is given priority. Others suggest that yield increases must be achieved through redoubled efforts to repeat the approaches of the green revolution; or that agricultural systems should embrace only biotechnology or become solely organic. What is clear despite these differences is that more will need to be made of existing agricultural land.

Agriculture in Kenya. Photo: Jules Pretty.

Patch intensification in Kenya. Photo: Jules Pretty.

Agriculture will, in short, have to be intensified. Traditionally agricultural intensification has been defined in three ways: i) increasing yields per hectare, ii) increasing cropping intensity (i.e. two or more crops) per unit of land or other inputs (water), or livestock intensity (e.g. faster maturing breeds), and iii) changing land use from low value crops or commodities to those that receive higher market prices or have better nutritional content.

Mucuna, Photo: Jules Pretty

Mucuna bean crops, Central America. Photo: Jules Pretty

The notion of “intensification” remains controversial to some, as recent successes in increasing food production per unit of resource have often also caused environmental harm and disruption to social systems.

The desire for agriculture to produce more food without environmental harm, or even positive contributions to natural and social capital, has been reflected in calls for a wide range of different types of more sustainable agriculture: for a ‘doubly green revolution’, for ‘alternative agriculture’, for an ‘evergreen revolution’, for ‘agroecological intensification’, for ‘green food systems’, for ‘greener revolutions’, and ‘evergreen agriculture’.

Multiple crops. Photo: Jules Pretty.

Multiple crops, Java. Photo: Jules Pretty.

Sustainable intensification (SI) is defined as a process or system where yields are increased without adverse environmental impact and without the cultivation of more land. The concept is thus relatively open, in that it does not articulate or privilege any particular vision of agricultural production. It emphasises ends rather than means, and does not predetermine technologies, species mix, or particular design components.


Pretty J. & Barucha Z.P. (2014). Sustainable intensification in agricultural systems, Annals of Botany, DOI: http://dx.doi.org/10.1093/aob/mcu205

Novel lineage-specific inversion and legume plastome evolution

Novel lineage-specific inversion and legume plastome evolution

Novel lineage-specific inversion and legume plastome evolution

Complete legume chloroplast genomes are only available for one Papilionoid clade, and information from other lineages is thus needed to better understand this family’s atypical evolution. Martin et al. sequence the plastome of Lupinus luteus, representing the Genistoid lineage, and perform comparative analyses at the structural and sequence levels. They discover a 36-kb inversion, embedded within the already known 50-kb inversion in the large single-copy region of the Papilionoideae. This inversion occurs at the base or soon after the Genistoid emergence, and most likely resulted from a flip-flop recombination. Mutational hotspots are also identified and new potentially informative regions for phylogenetic and molecular evolutionary studies in legumes are detected.

Scientists look for a common language in Himalaya ecology

The Himalaya range of mountains is famous all over the world. This is the world’s largest mountain range with fastest uplift rate hosts enormous physical as well as biological resources. The Himalayan region of Pakistan is actually the well known Western Himalayan Province famous for its unique flora and fauna of endemic and threatened nature. The Himalayas of Pakistan not only preserve the precious biodiversity but also provide precious ecosystem services including supporting, providing and cultural services. The Himalayan highlands of Pakistan provide uncountable environmental benefits and socioeconomics standing to the dwellers of the region. The area is blessed with the world’s highest plateaus, glaciers, snow fields, forests, wildlife and immense unexplored genetic resources.

Mountains of Pakistan

Mountains of Pakistan. Photo: Shujaul Mulk Khan.

To explore ecological issues in the Himalaya region, Hazara University, of Pakistan, is holding what is hoped to be just the first of a series of symposia on conservation issues. This symposium will not only gather the experts to discuss the potential and issue from different points of view but will also provide an opportunity to introduce the area internationally in terms of research and the ecotourism industry.

A trans-disciplinary symposium has the ability to draw together multiple researchers in different fields who might be tackling the same problems in isolation from each other. A recent review in Annals of Botany argued that we should be combining Importance Value Indices (IVIs) based on classifications of species assemblages and environmental biodiversity gradients and Use Values (UVs) that use anthropological methods to examine how local communities use different plants. This could be unexpectedly wide, as the difference in altitude over a small distance means one community could access many different ecological niches.

This local experience adds an important dimension to the accepted biodiversity conservation criteria – rarity, threat and endemism. Species can also have historical, traditional and educational values. These are values that are as much under threat as the plants themselves as urbanism encroaches on local communities, and could be a significant loss. For example ethnomedical knowledge can help recognise and preserve important species. If we do not pay attention to the loss this cultural practice, then its loss might also lead to losing the plant itself and any uses it might have.

The event will be held November 27-30, at Hazara University, Mansehra. The aim of this event will be to introduce the potential and problems of biodiversity and ecosystems of this region and to mitigate the issues through proper involvements of the relevant stakeholders.

Complete outcrossing in a monoecious clonal seagrass

Complete outcrossing in a monoecious clonal seagrass

Complete outcrossing in a monoecious clonal seagrass

Seagrasses are marine, flowering plants with a hydrophilous pollination strategy. Sinclair et al. study microsatellite DNA markers in order to understand the interactions between clonal structure, mating system and pollen dispersal in two seagrass meadows of Posidonia australis with contrasting local environmental conditions, one being exposed and the other being sheltered. The results show that in a system that appears to rely on chance pollination, all embryos are the result of outcrossed pollination. Pollen is thus being mixed in the water column, with local conditions having little influence on the success and pattern of pollination. Complete outcrossing suggests that post-pollination mechanisms may also be in place to prevent geitonogamous selfing.

Microgravity and chromosome damage

The Karyological Observations of Krikorian and O’Connor look at plant material from flights STS-2 and STS-3 of the Space Shuttle.

STS-2, among other things, carried a payload of Helianthus annuus, sunflowers. STS-2 was cut short from five days to two when a fuel cell for producing electricity and processing water failed. Despite this the plants had some time to grow, in a couple of cases with roots protruding from the soil. Krikorian and O’Connor say: “The soil environment of the roots in the HEFLEX-type modules was not particularly well suited to recovery of roots tips for karyological examination.” In plain English it sounds like it was extremely difficult, and they go on in the paper to explain some of the problems they had.

The key result was that when they looked at the cells, they found only around 2% were in division. The same plant in a lab would be expected to be ten times more active. They also found some plants had aneuploidy. Usually chromosomes come in pairs, (though polyploidy is common in plants too). In this case one plant was missing a partner for chromosome 6. The same was true in another plant from the sample. Given these results, similar tests followed on the STS-3 material.

Again with the oats, it was found that only a 2% of cells were in division, again about ten times less than anticipated from the lab. There was also chromosome damage. The mung beans too were found to have low counts for division, though less obvious signs of damage to the chromosomes.

It seems something was affecting the plants, but in their conclusions Krikorian and O’Connor were wary of saying exactly what. The obvious suspect is microgravity, but they also left open the possibility that it was the effect of launch and/or re-entry that was the problem. It’s this referring back to the control that marks out the value of the research on STS-3. It wasn’t simply that material was put into orbit, it was also that the same equipment was run on the ground to act as a control. If gravity is the variable you’re changing then it’s essential to get as much of the rest of the control experiment to run as closely to the orbital experiment as possible.

Like some of the other papers in this supplement, Karyological Observations has been cited this year in a paper Seed-to-Seed-to-Seed Growth and Development of Arabidopsis in Microgravity published October 2014 in Astrobiology. Link et al. also cite Kuang et al from 1996, Musgrave et al from 1998 and Kuang et al from 2000. In some ways it might be surprising that work from thirty years ago is still getting cited, but that’s how science works.

Currently NASA does plant science in orbit on the International Space Station, but this latest platform was built with the shuttle and the aging Russian Soyuz craft. In a similar way current plant research is built on the prior work of earlier scientists. Fortunately you don’t have to wait thirty years to see most research in Annals of Botany. If your library doesn’t have access to the journal, papers become free access a year after paper publication.

Space Shuttle landing

STS-3 lands at White Sands. Photo: NASA.

You can read more posts on papers from our spaceflight supplement by clicking the STS-3 tag.

Today’s Papers

Krikorian A.D. & O’Connor S.A. Karyological Observations, Annals of Botany, 54 (supp3) 49-63. DOI:

KUANG A. (1996). Cytochemical Localization of Reserves during Seed Development inArabidopsis thalianaunder Spaceflight Conditions, Annals of Botany, 78 (3) 343-351. DOI: http://dx.doi.org/10.1006/anbo.1996.0129

Kuang A. (2000). Influence of Microgravity on Ultrastructure and Storage Reserves in Seeds of Brassica rapa L., Annals of Botany, 85 (6) 851-859. DOI: http://dx.doi.org/10.1006/anbo.2000.1153

Link B.M. & Bratislav Stankovic (2014). Seed-to-Seed-to-Seed Growth and Development of Arabidopsis in Microgravity , Astrobiology, 14 (10) 866-875. DOI: http://dx.doi.org/10.1089/ast.2014.1184

MUSGRAVE M. (1998). Changes inArabidopsisLeaf Ultrastructure, Chlorophyll and Carbohydrate Content During Spaceflight Depend on Ventilation, Annals of Botany, 81 (4) 503-512. DOI: http://dx.doi.org/10.1006/anbo.1998.0585

Polyploidy and long-distance dispersal

Polyploidy and long-distance dispersal

Polyploidy and long-distance dispersal

Most of the numerous and remarkable range disjunctions across the southern oceans are probably the result of occasional long-distance dispersal, rather than of vicariance. Linder and Barker study the grass subfamily Danthonioideae, which probably reached its current global distribution by a number of long-distance dispersal events during the Neogene, and show that such dispersal is much more likely in polyploid than in diploid species. It is possible that polyploidy facilitates post-dispersal establishment, and it is postulated that the frequent occurrence of polyploidy in the grasses may thus have facilitated their long-distance dispersal, and hence contributed to the remarkable success of the family.