scholarly journals Fine root tradeoffs between nitrogen concentration and xylem vessel traits preclude unified whole‐plant resource strategies in Helianthus

2016 ◽  
Vol 6 (4) ◽  
pp. 1016-1031 ◽  
Author(s):  
Alan W. Bowsher ◽  
Chase M. Mason ◽  
Eric W. Goolsby ◽  
Lisa A. Donovan
Keyword(s):  
Fine Root ◽  
Nitrogen Concentration ◽  
Xylem Vessel ◽  
Plant Resource ◽  
Whole Plant

scholarly journals Mutations in the tomato gibberellin receptors suppress xylem proliferation and reduce water loss under water-deficit conditions

2020 ◽  
Vol 71 (12) ◽  
pp. 3603-3612 ◽  
Author(s):  
Natanella Illouz-Eliaz ◽  
Idan Nissan ◽  
Ido Nir ◽  
Uria Ramon ◽  
Hagai Shohat ◽  
...  
Keyword(s):  
Water Deficit ◽  
Water Status ◽  
Stomatal Closure ◽  
Normal Growth ◽  
Hydraulic Conductance ◽  
Xylem Vessel ◽  
Leaf Water Content ◽  
Whole Plant ◽  
Drought Conditions ◽  
Better Than

Abstract Low gibberellin (GA) activity in tomato (Solanum lycopersicum) inhibits leaf expansion and reduces stomatal conductance. This leads to lower transpiration and improved water status under transient drought conditions. Tomato has three GIBBERELLIN-INSENSITIVE DWARF1 (GID1) GA receptors with overlapping activities and high redundancy. We tested whether mutation in a single GID1 reduces transpiration without affecting growth and productivity. CRISPR-Cas9 gid1 mutants were able to maintain higher leaf water content under water-deficit conditions. Moreover, while gid1a exhibited normal growth, it showed reduced whole-plant transpiration and better recovery from dehydration. Mutation in GID1a inhibited xylem vessel proliferation, which led to lower hydraulic conductance. In stronger GA mutants, we also found reduced xylem vessel expansion. These results suggest that low GA activity affects transpiration by multiple mechanisms: it reduces leaf area, promotes stomatal closure, and reduces xylem proliferation and expansion, and as a result, xylem hydraulic conductance. We further examined if gid1a performs better than the control M82 in the field. Under these conditions, the high redundancy of GID1s was lost and gid1a plants were semi-dwarf, but their productivity was not affected. Although gid1a did not perform better under drought conditions in the field, it exhibited a higher harvest index.

scholarly journals Root growth and N dynamics in response to multi-year experimental warming, summer drought and elevated CO2 in a mixed heathland-grass ecosystem

2014 ◽  
Vol 41 (1) ◽  
pp. 1 ◽  
Author(s):  
M. F. Arndal ◽  
I. K. Schmidt ◽  
J. Kongstad ◽  
C. Beier ◽  
A. Michelsen
Keyword(s):  
Root Growth ◽  
Elevated Co2 ◽  
Environmental Changes ◽  
Nitrogen Concentration ◽  
N Uptake ◽  
Root Production ◽  
Summer Drought ◽  
Whole Plant ◽  
Grass Root ◽  
Biomass N

Ecosystems exposed to elevated CO2 are often found to sequester more atmospheric carbon due to increased plant growth. We exposed a Danish heath ecosystem to elevated CO2, elevated temperature and extended summer drought alone and in all combinations in order to study whether the expected increased growth would be matched by an increase in root nutrient uptake of NH4+-N and NO3– -N. Root growth was significantly increased by elevated CO2. The roots, however, did not fully compensate for the higher growth with a similar increase in nitrogen uptake per unit of root mass. Hence the nitrogen concentration in roots was decreased in elevated CO2, whereas the biomass N pool was unchanged or even increased. The higher net root production in elevated CO2 might be a strategy for the plants to cope with increased nutrient demand leading to a long-term increase in N uptake on a whole-plant basis. Drought reduced grass root biomass and N uptake, especially when combined with warming, but CO2 was the most pronounced main factor effect. Several significant interactions of the treatments were found, which indicates that the responses were nonadditive and that changes to multiple environmental changes cannot be predicted from single-factor responses alone.

scholarly journals Trehalose 6-phosphate signalling and impact on crop yield

2020 ◽  
Vol 48 (5) ◽  
pp. 2127-2137
Author(s):  
Matthew J. Paul ◽  
Amy Watson ◽  
Cara A. Griffiths
Keyword(s):  
Resource Allocation ◽  
Grain Yield ◽  
Green Revolution ◽  
Regulatory System ◽  
Grain Filling ◽  
Stem Height ◽  
Grain Number ◽  
Plant Resource ◽  
Whole Plant ◽  
Source Sink

The domestication and breeding of crops has been a major achievement for mankind enabling the development of stable societies and civilisation. Crops have become more productive per unit area of cultivated land over the course of domestication supporting a current global population of 7.8 billion. Food security crops such as wheat and maize have seen large changes compared with early progenitors. Amongst processes that have been altered in these crops, is the allocation of carbon resources to support larger grain yield (grain number and size). In wheat, reduction in stem height has enabled diversion of resources from stems to ears. This has freed up carbon to support greater grain yield. Green revolution genes responsible for reductions in stem height are known, but a unifying mechanism for the active regulation of carbon resource allocation towards and within sinks has however been lacking. The trehalose 6-phosphate (T6P) signalling system has emerged as a mechanism of resource allocation and has been implicated in several crop traits including assimilate partitioning and improvement of yield in different environments. Understanding the mode of action of T6P through the SnRK1 protein kinase regulatory system is providing a basis for a unifying mechanism controlling whole-plant resource allocation and source-sink interactions in crops. Latest results show it is likely that the T6P/SnRK1 pathway can be harnessed for further improvements such as grain number and grain filling traits and abiotic stress resilience through targeted gene editing, breeding and chemical approaches.

Revegetated Saline Pastures as a Forage Reserve for Sheep: 1. Effects of Season and Grazing on Morphology and Nutritive Value of Saltbush.

1999 ◽  
Vol 21 (1) ◽  
pp. 3 ◽  
Author(s):  
n Atiq-Ur-Rehma ◽  
JB Mackintosh ◽  
BE Warren ◽  
DR Lindsay
Keyword(s):  
Nutritional Value ◽  
Mineral Content ◽  
Nutritive Value ◽  
Nitrogen Concentration ◽  
Grazing Pressure ◽  
Dry Matter Digestibility ◽  
Plant Samples ◽  
Whole Plant ◽  
Number Of Stems ◽  
The Impact

This study determined the impact of grazing on the kind of material selected by sheep from a saltbush (Atriplex amnicola) plantation and the changes in the chemical composition of saltbush plants associated with season. Saltbush plants in four plots of about 0.9 hectares each were scored from 1 to 5 on the basis of leafiness. Ten Merino wethers were grazed on each plot, giving a stocking rate of about 11 per hectare. The results demonstrated that sheep selected only stem material of less than 1.5 mm diameter, while the grazing pressure on saltbush plants, as described by the number of stems eaten per 0.1 m2, increased from less than one to an average of 18 to 20 stems in 5 to 7 weeks. Grazing had a significant effect on dry matter digestibility (DMD) and nitrogen concentration of whole plant samples. During six weeks of grazing the DMD of whole plant samples cut 10 cm from the tips of the branches dropped from 0.53 to 0.25 (P<0.05), whereas the nitrogen content declined from 11 g/kg to 8 g/kg (P<0.05). At the end of grazing the nutritional value of whole plant samples was very poor and sheep refused to eat stem that was thicker than 1.5 mm. These findings question the grazable fraction reported in the literature for saltbush plantation. when the stem diameters used in calculations are not reported or thicker stems were assumed grazable. Season also had a significant effect on the ratio of leaf to stem and the mineral content. The concentration of sodium in saltbush leaf was negatively correlated (r = -0.93) with both nitrogen and potassium.

Nitrogen stress alters root proliferation in Douglas-fir seedlings

1990 ◽  
Vol 20 (9) ◽  
pp. 1524-1529 ◽  
Author(s):  
Alexander L. Friend ◽  
Marvin R. Eide ◽  
Thomas M. Hinckley
Keyword(s):  
Root Growth ◽  
Root System ◽  
Fine Roots ◽  
Fine Root ◽  
Douglas Fir ◽  
Chemical Activity ◽  
Nitrogen Stress ◽  
Root Proliferation ◽  
Whole Plant ◽  
Proliferation Response

The proliferation of roots in soil microenvironments was studied to gain an understanding of how nitrogen (N) stress affects root growth. By placing one major lateral root (<10% of the root system) of a Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) seedling into a small pot (microenvironment) and the remaining roots into a large pot, it was possible to manipulate the growth of a small part of the root system while having only minor effects on the growth of the entire seedling. Nitrogen stress was successfully induced by large-pot treatments and resulted in greatly decreased foliage growth and slightly decreased total fine (<2 mm diam.) root growth. Nitrogen stress had minimal effects on total fine root growth, but large effects on the distribution of growth within the root system. Fine roots grew preferentially in high compared with low N microenvironments, and root proliferation in high N microenvironments was enhanced twofold in N-stressed compared with nonstressed seedlings. The root proliferation response of Douglas-fir seedlings to N stress illustrates a potential means of N-stress compensation. It also implies that root distribution among soil microenvironments may depend not only upon chemical activity of nutrient ions in the rooting environment, but also upon nutrient stress in the whole plant.

Vertical patterns of fine root biomass, morphology and nitrogen concentration in a subalpine fir-wave forest

2010 ◽  
Vol 335 (1-2) ◽  
pp. 469-478 ◽  
Author(s):  
Shin Ugawa ◽  
Satoru Miura ◽  
Kojiro Iwamoto ◽  
Shinji Kaneko ◽  
Kenji Fukuda
Keyword(s):  
Root Biomass ◽  
Fine Root ◽  
Nitrogen Concentration ◽  
Fine Root Biomass ◽  
Subalpine Fir

Effects of increasing NaCl concentration on stem elongation, dry mass production, and macro- and micro-nutrient accumulation in Poncirus trifoliata

2000 ◽  
Vol 27 (1) ◽  
pp. 35 ◽  
Author(s):  
Ilhami Tozlu ◽  
Gloria A. Moore ◽  
Charles L. Guy
Keyword(s):  
Mass Production ◽  
Fine Root ◽  
Stem Elongation ◽  
Poncirus Trifoliata ◽  
Nutrient Accumulation ◽  
Whole Plant ◽  
Nacl Concentration ◽  
Leaf Tissues ◽  
Na Ions ◽  
Root Tissues

The effects of salinization with 0, 30, 60, 90, and 120 mМ sodium chloride (NaCl) on Poncirus trifoliata (L.) Raf. cv. Pomeroy were studied by means of stem elongation patterns, whole plant and tissue mass production, and mineral nutrient accumulation. The elements analyzed in leaf, stem, structural root and fine root tissues included Na, Cl, P, K, Ca, Mg, Mn, Fe, Cu, Al, and Zn. At the end of the 12-week experimental period, shoot length was reduced 30–80% in the 30 to 120 mМ NaCl treatments. The linear relationship found between stem elongation and salt concentration, and different tissues and salt concentration suggests that a 40–60 mМ NaCl concentration is optimal to test P. trifoliata or its progeny for salt stress. Root production was found to be continuous and plants apparently used this process as an avoidance mechanism to remove excess ions and delay onset of ion accumulation in this tissue. This phenomenon, designated ‘Fine Root Turnover’, is unique to P. trifoliata and may be used as a genetic resource to improve Citrus for salinity tolerance through intergeneric hybridization. Plants were able to delay accumulation of Na ions in leaves but not Cl ions, resulting in high Cl accumulation in leaves and accumulation of both ions in fine roots. The data suggested that, while Cl ions were more toxic in leaf tissues, Na ions were at least as toxic in fine root tissues. Among other nutrients, K was affected the most in response to salinity, decreasing within root tissues and increasing in leaf tissues with increased salin-ization. A similar phenomenon was observed for P levels in salinized tissues. Changes in tissue and whole plant accumulation patterns of the other tested elements as well as possible mechanisms for how excess Na and Cl ions are removed from and/or transported to less vulnerable tissues in Poncirus trifoliata during salinization are discussed.

Contrasting effects of two exotic invasive hemipterans on whole-plant resource allocation in a declining conifer

2015 ◽  
Vol 157 (1) ◽  
pp. 86-97 ◽  
Author(s):  
Nicole E. Soltis ◽  
Sara Gómez ◽  
Liahna Gonda-King ◽  
Evan L. Preisser ◽  
Colin M. Orians
Keyword(s):  
Resource Allocation ◽  
Plant Resource ◽  
Whole Plant ◽  
Exotic Invasive
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