Gene expression and nitrogen loss in senescing root systems of red clover (<i>Trifolium pratense</i>)

Webb, K. Judith; Jensen, Elaine; Heywood, Sue; Morris, Stephen M.; Linton, Patricia E.; Hooker, J. E.

doi:10.1017/s0021859610000420

Cited by 10 publications

(11 citation statements)

References 40 publications

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“…The legume has the potential to provide nitrogen (N) to the non-legume directly through mycorrhizal links, root exudates, or decay of roots and nodules (Jensen 1996a;Vandermeer 1999;Webb et al 2010). Another possible mechanism is that legumes can 'bank' large quantities of soil N, which might otherwise have leached out of the system, and release it through soil organic matter turnover to the non-legume companion crop later during the growing season, or to the following crops (Vinten et al 1992).…”

Section: Discussionmentioning

confidence: 99%

Legumes intercropped with spring barley contribute to increased biomass production and carry-over effects

Pappa¹,

Rees²,

Walker³

et al. 2011

J. Agric. Sci.

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Intercropping systems that include legumes can provide symbiotically fixed nitrogen (N) and potentially increase yield through improved resource use efficiency. The aims of the present study were: (a) to evaluate the effects of different legumes (species and varieties) and barley on grain yield, dry matter production and N uptake of the intercrop treatments compared with the associated cereal sole crop; (b) to assess the effects on the yields of the next grain crop and (c) to determine the accumulation of N in shoots of the crops in a low-input rotation. An experiment was established near Edinburgh, UK, consisting of 12 hydrologically isolated plots. Treatments were a spring barley (Hordeum vulgare cvar Westminster) sole crop and intercrops of barley/white clover (Trifolium repens cvar Alice) and barley/pea (Pisum sativum cvar Zero4 or cvar Nitouche) in 2006. All the plots were sown with spring oats (Avena sativa cvar Firth) in 2007 and perennial ryegrass in 2008. No fertilizers, herbicides or pesticides were used at any stage of the experiment. Above-ground biomass (barley, clover, pea, oat and ryegrass) and grain yields (barley, pea and oat) were measured at key stages during the growing seasons of 2006, 2007 and 2008; land equivalent ratio (LER) was measured only in 2006. At harvest, the total above-ground biomass of barley intercropped with clover (4·56 t biomass/ha) and barley intercropped with pea cvar Zero4 (4·49 t biomass/ha) were significantly different from the barley sole crop (3·05 t biomass/ha; P < 0·05). The grain yield of the barley (2006) intercropped with clover (3·36 t grain/ha) was significantly greater than that in the other treatments (P < 0·01). The accumulation of N in barley was low in 2006, but significantly higher (P < 0·05) in the oat grown the following year on the same plots. The present study demonstrates for the first time that intercrops can affect the grain yield and N uptake of the following crop (spring oats) in a rotation. Differences were also linked to the contrasting legume species and cultivars present in the previous year's intercrop. Legume choice is essential to optimize the plant productivity in intercropping designs. Cultivars chosen for intercropping purposes must take into account the effects upon the growth of the partner crop/s as well as to the following crop, including environmental factors.

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Section: Discussionmentioning

confidence: 99%

Legumes intercropped with spring barley contribute to increased biomass production and carry-over effects

Pappa¹,

Rees²,

Walker³

et al. 2011

J. Agric. Sci.

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“…This is somewhat a different view on the role of plant proteases under stress, specifically wheat CPs, whereby an increase in their stress‐associated expression in leaves was proposed as a marker of susceptibility to water‐deficit (Simova‐Stoilova et al 2010). A similar study conducted on the roots of red clover did not show an increase in CPs till after 21 days of stress, after which the roots were terminally consigned to senescence (Webb et al 2010). Nevertheless, preliminary results from our laboratory combined with extensive information gleaned from rice expression databases clearly implicate a role for rice root proteases in compensating for the nitrogen stress concomitant to drought.…”

Section: Introductionmentioning

confidence: 86%

Root proteases: reinforced links between nitrogen uptake and mobilization and drought tolerance

Kohli

Narciso

Miró

et al. 2012

Physiologia Plantarum

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Integral subcellular and cellular functions ranging from gene expression, protein targeting and nutrient supply to cell differentiation and cell death require proteases. Plants have unique organelles such as chloroplasts composed of unique proteins that carry out the unique process of photosynthesis. Hence, along with proteases common across kingdoms, plants contain unique proteases. Improved knowledge on proteases can lead to a better understanding of plant development, differentiation and death. Because of their importance in multiple processes, plant proteases are actively studied. However, root proteases specifically are not as well studied. The associated rhizosphere, organic matter and/or inorganic matter make roots a difficult system. Yet recent research conclusively demonstrated the occurrence of endocytosis of proteins, peptides and even microbes by root cells, which, hitherto known for specialized pathogenesis or symbiosis, was unsuspected for nutrient uptake. These results reinforced the importance of root proteases in endocytosis or root exudate-mediated nutrient uptake. Rhizoplane, rhizosphere or in planta protease action on proteins, peptides and microbes generates sources of nitrogen, especially during abiotic stresses such as drought. This article highlights the recent research on root proteases for nitrogen uptake and the connection of the two to drought-tolerance mechanisms. Drought-induced proteases in rice roots, as known from rice expression databases, are discussed for future research on certain M50, Deg, FtsH, AMSH and deubiquitination proteases. The recent emphasis on linking drought and plant hydraulics to nutrient metabolism is illustrated and connected to the value of a systematic study of root proteases in crop improvement.

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“…Root longevity, which was defined as the time span until more than 80% of root cells lost viability after shoot excision, was mostly affected by the light environment and the soil temperature, and in general, root senescence was strongly negatively correlated with sugar contents. Webb et al (2010) also studied root senescence and nitrogen release in the same species after temporary or prolonged abiotic stress. Results showed a strong nitrogen release from roots under prolonged stress, which indicated the start of cellular breakdown (i.e.…”

Section: Senescencementioning

confidence: 99%

“…loss of membrane integrity) of the root system, coinciding with the failure of plants to recover. Interestingly, Webb et al (2010) characterized a cysteine protease gene (Tp-cp8) that may be of particular importance for root senescence in this species. In a comparative study of root senescence across four species, including Populus tremuloides, Acer rubrum, A. saccharum, and Betula alleghaniensis, Kunkle et al (2009) evaluated the changes in fine root biomass and nitrogen contents from live to dead roots.…”

Section: Senescencementioning

confidence: 99%

Perennial Roots to Immortality ,

Munné‐Bosch

2014

Plant Physiology

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Maximum lifespan greatly varies among species, and it is not strictly determined; it can change with species evolution. Clonal growth is a major factor governing maximum lifespan. In the plant kingdom, the maximum lifespans described for clonal and nonclonal plants vary by an order of magnitude, with 43,600 and 5,062 years for Lomatia tasmanica and Pinus longaeva, respectively. Nonclonal perennial plants (those plants exclusively using sexual reproduction) also present a huge diversity in maximum lifespans (from a few to thousands of years) and even more interestingly, contrasting differences in aging patterns. Some plants show a clear physiological deterioration with aging, whereas others do not. Indeed, some plants can even improve their physiological performance as they age (a phenomenon called negative senescence). This diversity in aging patterns responds to species-specific life history traits and mechanisms evolved by each species to adapt to its habitat. Particularities of roots in perennial plants, such as meristem indeterminacy, modular growth, stress resistance, and patterns of senescence, are crucial in establishing perenniality and understanding adaptation of perennial plants to their habitats. Here, the key role of roots for perennial plant longevity will be discussed, taking into account current knowledge and highlighting additional aspects that still require investigation.

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Gene expression and nitrogen loss in senescing root systems of red clover (Trifolium pratense)

Cited by 10 publications

References 40 publications

Legumes intercropped with spring barley contribute to increased biomass production and carry-over effects

Legumes intercropped with spring barley contribute to increased biomass production and carry-over effects

Root proteases: reinforced links between nitrogen uptake and mobilization and drought tolerance

Perennial Roots to Immortality ,

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