Soluble Carbohydrates In Shoots Research Articles

Identification of Root-Associated Bacteria That Influence Plant Physiology, Increase Seed Germination, or Promote Growth of the Christmas Tree Species Abies nordmanniana.

Abies nordmanniana is used for Christmas tree production but poor seed germination and slow growth represent challenges for the growers. We addressed the plant growth promoting potential of root-associated bacteria isolated from A. nordmanniana. Laboratory screenings of a bacterial strain collection yielded several Bacillus and Paenibacillus strains that improved seed germination and produced indole-3-acetic acid. The impact of three of these strains on seed germination, plant growth and growth-related physiological parameters was then determined in greenhouse and field trials after seed inoculation, and their persistence was assessed by 16S rRNA gene-targeted bacterial community analysis. Two strains showed distinct and significant effects. Bacillus sp. s50 enhanced seed germination in the greenhouse but did not promote shoot or root growth. In accordance, this strain did not increase the level of soluble hexoses needed for plant growth but increased the level of storage carbohydrates. Moreover, strain s50 increased glutathione reductase and glutathione-S-transferase activities in the plant, which may indicate induction of systemic resistance during the early phase of plant development, as the strain showed poor persistence in the root samples (rhizosphere soil plus root tissue). Paenibacillus sp. s37 increased plant root growth, especially by inducing secondary root formation, under in greenhouse conditions, where it showed high persistence in the root samples. Under these conditions, it further it increased the level of soluble carbohydrates in shoots, and the levels of starch and non-structural carbohydrates in roots, stem and shoots. Moreover, it increased the chlorophyll level in the field trial. These findings indicate that this strain improves plant growth and vigor through effects on photosynthesis and plant carbohydrate reservoirs. The current results show that the two strains s37 and s50 could be considered for growth promotion programs of A. nordmanniana in greenhouse nurseries, and even under field conditions.

Oat phenotypes for drought adaptation and yield potential

We measured yield and its components, phenology, leaf greenness, and concentration of water soluble carbohydrates and concentration of nitrogen in shoots of 29 oat varieties to determine (i) the phenotypic plasticity of these traits as a means to capture genotype-by-environment interactions, (ii) the role of these traits and their plasticity in adaptation to drought, and (iii) putative trade-offs between drought adaptation and yield potential. Varieties spaned grain, hay and grazing types, and ranged from 1301 to 1927°Cd from sowing to anthesis. Yield was measured in nine environments while other traits were measured in 4–7 out of the 9 environments. Averaged across varieties, yield varied from 0.3 to 4.2tha−1. The main environmental drivers of yield were water supply:demand from 500°Cd before to 500°Cd after anthesis, and minimum temperature in the same period. Phenotypic plasticity of yield, quantified as variance ratio, ranged from 0.60 to 1.22 for grain types and from 0.28 to 1.06 for their grazing and hay counterparts; high yield plasticity was associated with an asymmetric response to growing conditions: yield increased 3.3±0.28tha−1 per unit increase in plasticity under favourable conditions, and 0.6±0.16tha−1 per unit increase in plasticity under stress. For our combination of varieties and environments, genotypes were better discriminated in favourable environments, where selection for high plasticity would improve both yield potential and drought adaptation. After accounting for plasticity, yield residuals revealed consistent phenological thresholds (943°Cd for GS31, 1470°Cd for GS60) for adaptation to both favourable and stressful conditions. Yield correlated with leaf greenness (SPAD), particularly during grain fill. As expected from theory, yield was closely related to grains per m2 and weakly related to grain weight. Grains per m2 were negatively related to concentration of water soluble carbohydrates in shoots, which were in turn negatively correlated with shoot nitrogen concentration. Under favourable conditions, some varieties maintained a high concentration (>20%) of water soluble carbohydrates at harvest. Selection against this trait could improve yield potential, but residual labile carbohydrates can also be exploited in dual grain-feed varieties, and can provide flexibility for hay growers when logistics preclude cutting at the common water ripe (GS71) target.

Arbuscular mycorrhizal inoculation increases biomass of Euterpe edulis and Archontophoenix alexandrae after two years under field conditions

Inoculation with arbuscular mycorrhizal fungi (AMF) of tree seedlings in the nursery is a biotechnological strategy to improve growth, survival after transplanting, biomass production and to reduce the use of fertilizers. Archontophoenix alexandrae and Euterpe edulis are palm species used in southern Brazil to produce the palm heart, the latter being included in the list of threatened species due to the overexploitation of its native population. The purpose of this paper was to evaluate the effect of mycorrhizal inoculation on growth and physiological parameters of A. alexandrae and E. edulis. After germination, the seedlings were inoculated (AMF) or not (CTL) with AMF in the treatments. Values of chlorophyll content, biomass and shoot phosphorus were not statistically different between the AMF and CTL treatments, after five months in the greenhouse. Inoculation with AMF significantly increased the levels of starch and soluble carbohydrates in shoots and roots of both species. Under field conditions, AMF had no effect on stem diameter and height after 12 and 24 months, but total plant biomass and leaf, stem and root biomass were greater in AMF than in CTL plants. The data indicated that AMF inoculation in the nursery has a strong effect on biomass accumulation after growing for 24 months under field conditions. Therefore, AMF inoculation should be considered an important strategy to increase growth and production of these economically important tropical palm species.

Soluble carbohydrate content of shoots of Arctic wetland plants that are consumed by lesser snow geese

We recorded seasonal changes in the total amounts of soluble carbohydrates in shoots of salt- and fresh-water coastal plants at La Pérouse Bay, northern Manitoba, to determine whether adult snow geese and their goslings selected forage rich in soluble carbohydrates during the breeding season. The selection of forage plants in spring and summer by adults and goslings was strongly linked to the presence of high amounts of soluble carbohydrates in tissues: on the order of 100 mg·g–1 dry mass. When the content fell as a result of shoot development or leaf senescence, the geese switched to alternative sources of forage. The extent to which individual shoots rich in soluble carbohydrates of the primary freshwater forage species are grazed depends on the local density of breeding geese at the study site, which has fallen in the last decade as a result of the earlier destruction of much of the coastal vegetation by foraging geese.

Exogenous Abscisic Acid Increases Carbohydrate Accumulation and Redistribution to the Grains in Wheat Grown Under Field Conditions of Soil Water Restriction

This work investigates the effects of abscisic acid (ABA) on physiologic parameters related to yield in wheat (Triticum aestivum) grown under field conditions with water restriction ranging between 45.7% and 49.5% of field capacity during anthesis and postanthesis. ABA (300 mg L−1) was sprayed onto the plants at the beginning of shoot lengthening which significantly promoted leaf area and higher concentrations of chlorophylls and carotenoids in flag leaf at anthesis. ABA also increased soluble carbohydrates in shoots at anthesis, which were then re-exported to the grains at maturity. This correlated with a yield increase that was achieved by a higher number and weight of grains per spike, but protein content was not significantly affected.

The influence of IAA, carbohydrate and mineral concentration in host tissue on ectomycorrhizal development on Pinus sylvestris L. in relation to nutrient supply

summaryConcentrations of indole‐3‐acetie acid (IAA) in lateral roots, fungal biomasa (ergosterol) in lateral roots and extrametrical mycelium, and carbohydrates and minerals in shoots were measured in mycorrhizal and non‐mycorrhizal Pinus sylvestris L. seedlings supplied with different amounts of N and P. IAA concentrations in lateral roots of mycorrhizal seedlings were the same or lower than those in control seedlings. The concentrations of IAA in mycorrhizal root tips of Laccaria bicolor inoculated seedlings were 40% lower than those in lateral roots. IAA concentrations in lateral roots of L. color‐inoculated seedlings were positively related to X supply. A rise in N supply reduced the development of extramatrical mycelium of L. bicolor and the fungal biomass in lateral roots of Hebeloma crustuliniforme‐inoculated seedlings. High N supply reduced concentrations of starch, Ca and Mg in shoots but increased those of glucose and fructose. P had no effect on fungal growth or on concentrations of IAA. Fungal growth was negatively correlated with levels of soluble carbohydrates in shoots, shoot concentrations of N, P and K, relative growth rate and the shoot: root ratio of the seedlings. Starch, Mg and Ca concentrations in the shoot were positively correlated with fungal growth. No support was found for the hypothesis that IAA is important in regulating mycorrhizal colonization.

Long-term oxygen shortage induces sugar accumulation – particularly fructans in wheat seedlings

SynopsisIn response to long-term oxygen shortage in the rooting medium (>7days), there was an accumulation of soluble carbohydrates in shoots as well as in roots of wheat seedlings (Triticum aestivum L. cv. Alcedo). The content of fructo-oligosaccharides had increased five-fold in the roots and seven-fold in the shoots. This fails to fit the assumption that higher substrate consumption is accompanied by the fermentation under oxygen shortage.

Fructan content of wheat seedlings (Triticum aestivum L.) under hypoxia and following re-aeration.

We studied fructan accumulation in wheat seedlings (Triticum aestivum L. cv. Alcedo) caused by oxygen shortage around the root. Plants were cultivated in either nitrogen-flushed or aerated nutrient solution. In response to the nitrogen treatment there was an accumulation of soluble carbohydrates in shoots as well as in roots. The main contribution was due to fructans. The content of fructo-oligosaccharides had been increased five-fold in the roots and seven-fold in the shoots. This is incompatible with the assumption that higher substrate consumption follows enhanced fermentation under oxygen shortage. Re-aeration of the nitrogen-flushed nutrient solution resulted in enhanced consumption of stored carbohydrates, mainly of fructans, accompanied by high growth rates of the roots. The possibility of utilizing fructans quickly if oxygen is available is a possible advantage for plants adapted to hypoxia. Particularly however, it is suggested that the low energy requirements for sucrose: sucrose fructosyl transferase, allowing fructan synthesis even under oxygen shortage, may improve the fitness of plants to survive temporary hypoxia in the rhizosphere.