Different photosynthetic acclimation mechanisms are activated under waterlogging in two contrasting Lolium perenne genotypes

2016 ◽  
Vol 43 (10) ◽  
pp. 931 ◽  
Author(s):  
Barbara Jurczyk ◽  
Ewa Pociecha ◽  
Janusz Košcielniak ◽  
Marcin Rapacz
Keyword(s):  
Low Temperature ◽  
Cold Acclimation ◽  
Lolium Perenne ◽  
Perennial Ryegrass ◽  
Feedback Inhibition ◽  
Water Soluble ◽  
Photosynthetic Acclimation ◽  
Soluble Carbohydrates ◽  
Bisphosphate Carboxylase ◽  
Water Soluble Carbohydrates

Increased precipitation and snowmelt during warmer winters may lead to low-temperature waterlogging of plants. Perennial ryegrass (Lolium perenne L.) is one of the most important cool-season grasses in agriculture. It is well adapted to cold climates, and may be considered as a model system for studying the mechanisms involved in cold acclimation. The aim of this study was to evaluate the effects of waterlogging on photosynthetic acclimation to cold in perennial ryegrass. Two L. perenne genotypes that differ in their responses to waterlogging in terms of freezing tolerance were compared. We evaluated the effects of waterlogging during cold acclimation on the water-soluble carbohydrate concentration, ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) activity, photochemical efficiency of PSII, and transcript levels of the Rubisco activase (RcaA) and sucrose-sucrose fructosyltransferase (1-SST) genes. The genotype that did not accumulate water-soluble carbohydrates in the leaf under waterlogging showed a lower degree of feedback inhibition of photosynthesis under low temperature, and activated a photochemical mechanism of photosynthetic acclimation to cold. The other genotype accumulated water-soluble carbohydrates in the leaf during waterlogging, and activated a non-photochemical mechanism under cold conditions. Different photosynthetic acclimation systems to cold under waterlogging may be activated in these two contrasting L. perenne genotypes.

scholarly journals Storing carbon in leaf lipid sinks enhances perennial ryegrass carbon capture especially under high N and elevated CO2

2019 ◽  
Vol 71 (7) ◽  
pp. 2351-2361 ◽  
Author(s):  
Zac Beechey-Gradwell ◽  
Luke Cooney ◽  
Somrutai Winichayakul ◽  
Mitchell Andrews ◽  
Shen Y Hea ◽  
...  
Keyword(s):  
Leaf Area ◽  
Perennial Ryegrass ◽  
Lipid Droplets ◽  
Feedback Inhibition ◽  
Leaf Growth ◽  
Water Soluble ◽  
Atmospheric Co2 ◽  
Soluble Carbohydrates ◽  
Elevated Atmospheric Co2 ◽  
N Supply

Abstract By modifying two genes involved in lipid biosynthesis and storage [cysteine oleosin (cys-OLE)/diacylglycerol O-acyltransferase (DGAT)], the accumulation of stable lipid droplets in perennial ryegrass (Lolium perenne) leaves was achieved. Growth, biomass allocation, leaf structure, gas exchange parameters, fatty acids, and water-soluble carbohydrates were quantified for a high-expressing cys-OLE/DGAT ryegrass transformant (HL) and a wild-type (WT) control grown under controlled conditions with 1–10 mM nitrogen (N) supply at ambient and elevated atmospheric CO2. A dramatic shift in leaf carbon (C) storage occurred in HL leaves, away from readily mobilizable carbohydrates and towards stable lipid droplets. HL exhibited an increased growth rate, mainly in non-photosynthetic organs, leading to a decreased leaf mass fraction. HL leaves, however, displayed an increased specific leaf area and photosynthetic rate per unit leaf area, delivering greater overall C capture and leaf growth at high N supply. HL also exhibited a greater photosynthesis response to elevated atmospheric CO2. We speculate that by behaving as uniquely stable microsinks for C, cys-OLE-encapsulated lipid droplets can reduce feedback inhibition of photosynthesis and drive greater C capture. Manipulation of many genes and gene combinations has been used to increase non-seed lipid content. However, the cys-OLE/DGAT technology remains the only reported case that increases plant biomass. We contrast cys-OLE/DGAT with other lipid accumulation strategies and discuss the implications of introducing lipid sinks into non-seed organs for plant energy homeostasis and growth.

Milk production and composition of dairy cows grazing two perennial ryegrass cultivars allocated in the morning and afternoon

2017 ◽  
Vol 57 (7) ◽  
pp. 1507 ◽  
Author(s):  
A. Chen ◽  
R. H. Bryant ◽  
G. R. Edwards
Keyword(s):  
Dairy Cows ◽  
Milk Production ◽  
Perennial Ryegrass ◽  
Nutritive Value ◽  
Morphological Characteristics ◽  
Ground Level ◽  
Water Soluble ◽  
Soluble Carbohydrates ◽  
Above Ground Level ◽  
Water Soluble Carbohydrates

The objective of the study was to evaluate the effect of perennial ryegrass cultivar and timing of herbage allocation on herbage nutritive value and milk production of mid-lactation dairy cows. An autumn grazing trial using 48 Friesian × Jersey spring-calving cows was conducted over 10 days. Twelve groups of four cows were allocated to three replicates of four treatments, namely, two perennial ryegrass cultivars (AberMagic or Prospect) offered either after milking in the morning (0830 hours) or afternoon (1630 hours). Cows were offered a daily herbage allowance of 30 kg DM/cow above ground level. There were no significant differences in sward structure and morphological characteristics between cultivars, except for Prospect having a lower average tiller mass (43.1 mg) than AberMagic (48.4 mg). The concentration of water-soluble carbohydrates (WSC) and organic matter digestibility in DM (DOMD) was greater in AberMagic (180 g/kg, 74.2%) than in Prospect (153 g/kg, 71.4%). Herbage DM percentage, WSC concentration and DOMD were lower in the morning than in the afternoon (18.8% vs 22.3% DM; 154 vs 179 g/kg WSC; 72.1% vs 73.5% DOMD). Herbage DM intake (12.0 kg/cow.day), milk yield (17.2 kg/cow.day) and milksolids yield (1.60 kg/cow.day) did not differ significantly among treatments. Cultivar choice and timing of allocation influenced herbage WSC concentration and digestibility, but did not alter milksolids production.

scholarly journals The Effect of Drying Methods on Water-Soluble Carbohydrates and Crude Protein Concentrations and Their Ratio in Two Perennial Ryegrass Cultivars

Agronomy ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 383 ◽  
Author(s):  
Cristian J. Moscoso ◽  
Sarah A. Morgan ◽  
M. Jordana Rivero
Keyword(s):  
Perennial Ryegrass ◽  
Crude Protein ◽  
Freeze Drying ◽  
Joint Effect ◽  
Water Soluble ◽  
Soluble Carbohydrates ◽  
Drying Methods ◽  
Drying Method ◽  
Freeze Dried ◽  
Water Soluble Carbohydrates

The objective of this study was to assess the joint effect of perennial ryegrass cultivars and drying methods on concentrations of water-soluble carbohydrates (WSC) and crude protein (CP) and WSC/CP ratio. AberMagic AR1 and Expo AR1 forage were collected in December 2016, March, June, September and November 2017 and either oven-dried at 60 °C for 48 h (OD_60), at 80 °C for 16 h (OD_80), frozen at −80 °C for 48 h then freeze-dried (−80_FD), or flash-frozen with liquid N then freeze-dried (LN_FD). Data were analyzed by ANOVA in a factorial design with cultivar and drying method as factors. AberMagic AR1 had between 9.0 to 31.5% higher WSC concentration than Expo AR1 in the four samplings. Freeze-drying preserved more WSC than oven-drying treatments (+22.7%), particularly in June. The CP concentration of Expo AR1 was higher only in December (+6.8%), and was 22.9 and 10.9% higher in OD_60 samples compared to LN_FD samples in December and November, respectively. The WSC/CP ratio varied in June, being greater in AberMagic AR1 (+36.1%). Drying method affected WSC/CP ratio in December, June and November where freeze-drying produced greater ratios. Drying techniques generated differences in WSC, CP and WSC/CP ratio, which may affect the accuracy of the estimated impacts of forages on productivity and N use efficiency.

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