Plant-soluble carbohydrate reserves and senescence - key criteria for developing an effective grazing management system for ryegrass-based pastures: a review

2001 ◽  
Vol 41 (2) ◽  
pp. 261 ◽  
Author(s):  
W. J. Fulkerson ◽  
D. J. Donaghy
Keyword(s):  
Dairy Cattle ◽  
Root Growth ◽  
Photosynthetic Capacity ◽  
Water Soluble ◽  
The Other ◽  
Soluble Carbohydrates ◽  
Soluble Carbohydrate ◽  
Carbohydrate Reserves ◽  
Water Soluble Carbohydrates ◽  
Water Soluble Carbohydrate

This review examines the use of changes in soluble carbohydrate reserves, and the onset of senescence in ryegrass (Lolium spp.), as key criteria for successfully managing an intermittent grazing system for dairy cattle. Ryegrass is a ‘3-leaf ’ plant; that is, only about 3 green leaves/tiller exist at any one time with the initiation of a new leaf coinciding with senescence of the oldest fourth leaf. Thus, grazing pasture older than 3 leaves/tiller will not only lead to wastage of pasture but also the senescent material will reduce overall quality of herbage. Based on this, the time taken for 3 new leaves/tiller to regrow sets the maximum grazing interval. On the other hand, in a well-utilised dairy pasture, most ryegrass leaf has been removed and the plant relies on stored water-soluble carbohydrate reserves to grow new shoots and hence regain photosynthetic capacity. If the concentration of water-soluble carbohydrates is inadequate, because there has been insufficient time to replenish in the previous inter-grazing period, regrowth will be suppressed and this may also affect persistence in the longer term. Immediately after grazing, water-soluble carbohydrate reserves decline as they are used to regrow new shoots, and root growth stops. It is not until about 3/4 of a new leaf/tiller has regrown that the plant has adequate photosynthetic capacity for growth and maintenance and only then does water-soluble carbohydrate replenishment and root growth commence. Studies have shown that subsequent regrowth is suppressed if plants are redefoliated before the 2 leaves/tiller stage of regrowth. Also, the levels of potassium and nitrogen (as nitrates and other non-protein nitrogen products) may be very high and cause metabolic problems in stock grazing such pasture. Thus, replenishment of water-soluble carbohydrate reserves sets the minimum grazing interval at 2 leaves/tiller. The rate of accumulation of water-soluble carbohydrates in the plant is a function of input through photosynthesis (source) and output to growth and respiration (sinks). Thus, apart from grazing interval (which sets the time to replenish water-soluble carbohydrate plant reserves), water-soluble carbohydrate storage will be influenced by incoming solar radiation (cloud cover, day length, pasture canopy density) and energy needs of the plant through respiration (temperature, canopy mass) and growth. Relating grazing interval to leaf number places the emphasis on the readiness of plants to be grazed rather than on the animals’ requirements, with leaf appearance interval depending primarily on ambient temperature. This allows grazing interval to be expressed in a similar morphological stage of growth, irrespective of season or location. Setting grazing interval on these 2 criteria has been shown to maximise growth and persistence of ryegrass and optimise the levels of most nutrients in pasture required by dairy cattle including protein, water-soluble carbohydrates, calcium, potassium and magnesium. Metabolisable energy and fibre do not change appreciably up to the 3 leaves/tiller stage of regrowth. On the other hand, grazing pasture before 2 leaves/tiller not only retards regrowth and reduces persistence, it provides forage too high in potassium and protein (nitrates) and too low in water-soluble carbohydrates for dairy cattle.

scholarly journals Changes in root porosity and water soluble carbohydrates in rice (Oryza sativa L.) under submergence stress

2019 ◽  
Vol 17 (4) ◽  
pp. 539-544
Author(s):  
Md Juiceball Hassan ◽  
Md Masudul Karim ◽  
Md Amirul Islam ◽  
Md Habibur Rahman Pramanik ◽  
Md Alamgir Hossain
Keyword(s):  
Stress Condition ◽  
Water Soluble ◽  
Soluble Carbohydrates ◽  
Soluble Carbohydrate ◽  
Susceptible Cultivar ◽  
Rice Cultivars ◽  
Root Porosity ◽  
Submergence Stress ◽  
Water Soluble Carbohydrates ◽  
Water Soluble Carbohydrate

Submergence stress at early vegetative stage is one of the most important constraints in the productivity of rice in Bangladesh. Submergence causes yield loss of rice at Aman season in Bangladesh and therefore, it is necessary to develop submergence tolerant rice cultivars. A pot experiment was conducted at the net house of Department of Crop Botany, Bangladesh Agricultural University, during Aman season from July to December, 2017 to evaluate the changes in root porosity and water soluble carbohydrates (WSCs) associated with submergence tolerance in rice. The experiment consisted of two factors—(i) Rice cultivars (Binadhan-11, Binadhan-12, BRRI dhan51 and BRRI dhan52 as tolerant and BRRI dhan49 as susceptible) and(ii) Submergence stress: Submergence for 14 days at vegetative stage and control. Submergence stress was imposed by dipping of pots into a water tank with about 90 cm depth of water while the control plants are maintained in the pot house of the field laboratory. The plants were sampled at seven days interval during submergence to determine the changes in root porosity and to examine the contribution of shoot reserves for their survival. The root porosity was measured by pycnometer method and water soluble carbohydrate was measured by the anthrone method. Tolerant cultivars showed greater root porosity development in both control and stress condition but the susceptible cultivar showed significantly lower root development in stress condition. Higher root porosity might help tolerant cultivars to survive in submergence stress more efficiently. Tolerant rice cultivars had high initial soluble carbohydrate than the susceptible one. Under submergedcondition, the tolerant cultivars showed slow depletion of water soluble carbohydrate compared to susceptible cultivar. Higher carbohydrate contents in tolerant cultivars might act as buffer stock during submergence for their better survival and growth. J Bangladesh Agril Univ 17(4): 539–544, 2019

scholarly journals An Overview on the Factors Affecting Water-soluble Carbohydrates Concentration during Ensiling of Silage

2021 ◽  
Vol 3 (1) ◽  
pp. 63-80
Author(s):  
Muhammad Fraz Ali ◽  
Muhammad Tahir
Keyword(s):  
Dry Matter ◽  
Water Soluble ◽  
Soluble Carbohydrates ◽  
Soluble Carbohydrate ◽  
Factors Affecting ◽  
Carbohydrate Concentration ◽  
Forage Species ◽  
Water Soluble Carbohydrates ◽  
Increasing Temperature ◽  
Water Soluble Carbohydrate

Water-soluble carbohydrates (WSC) concentration during the ensiling process is influenced by both controllable and uncontrollable factors such as temperature, moisture level, fertilizers, additives nutrients, and time of ensiling of silage. The WSC contents may vary among the different fodder and forage species. The ensiling temperature has a limiting impact on water-soluble carbohydrates and their concentration decrease with increasing temperature. Crops should be harvested at optimum moisture and dry matter level to reach the required concentration of water-soluble carbohydrates to produce organic acids. Water-soluble carbohydrate concentration decreased with the crop's maturity due to the accumulation of carbohydrates in the grains. The evening cut has more concentration of WSC than that of the morning cut due to the photosynthesis process. The contents of WSC can be increased by using different kinds of additives during the ensiling process. Ensiling time has not much influence on the water-soluble carbohydrates. To understand these factors, we have a detailed review of the factors affecting the WSC of silage.

Changes in water soluble carbohydrate content during the day in Lucerne and Fescue cut in autumn

2003 ◽  
Vol 2003 ◽  
pp. 176-176
Author(s):  
J. L. Repetto ◽  
N. Errandonea ◽  
A. Britos ◽  
D. Cozzolino* ◽  
C. Cajarville
Keyword(s):  
Plant Species ◽  
Carbohydrate Content ◽  
Water Soluble ◽  
Soluble Carbohydrates ◽  
Soluble Carbohydrate ◽  
Microbial Synthesis ◽  
Water Soluble Carbohydrates ◽  
Water Soluble Carbohydrate ◽  
Different Parts

The content of water-soluble carbohydrates (WSC) in plants is variable, and depends on plant species and environment conditions. This content may be the limitation for the fermentation during silage making and also for microbial synthesis in rumen. The objective of this study was to measure the variations of the WSC in temperate forages, during autumn, in different moments of the day and in different parts of the plant.

scholarly journals Response of Bromus valdivianus (Pasture Brome) Growth and Physiology to Defoliation Frequency Based on Leaf Stage Development

Agronomy ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 2058
Author(s):  
Iván P. Ordóñez ◽  
Ignacio F. López ◽  
Peter D. Kemp ◽  
Daniel J. Donaghy ◽  
Yongmei Zhang ◽  
...  
Keyword(s):  
Growth Rate ◽  
Stomatal Conductance ◽  
Root Growth ◽  
Water Soluble ◽  
Soluble Carbohydrates ◽  
Leaf Stage ◽  
Water Soluble Carbohydrates ◽  
Stage Development ◽  
Defoliation Frequency ◽  
Root Growth Rate

The increase in drought events due to climate change have enhanced the relevance of species with greater tolerance or avoidance traits to water restriction periods, such as Bromus valdivianus Phil. (B. valdivianus). In southern Chile, B. valdivianus and Lolium perenne L. (L. perenne) coexist; however, the pasture defoliation criterion is based on the physiological growth and development of L. perenne. It is hypothesised that B. valdivianus needs a lower defoliation frequency than L. perenne to enhance its regrowth and energy reserves. Defoliation frequencies tested were based on B. valdivianus leaf stage 2 (LS-2), leaf stage 3 (LS-3), leaf stage 4 (LS-4) and leaf stage 5 (LS-5). The leaf stage development of Lolium perenne was monitored and contrasted with that of B. valdivianus. The study was conducted in a glasshouse and used a randomised complete block design. For Bromus valdivianus, the lamina length, photosynthetic rate, stomatal conductance, tiller number per plant, leaf area, leaf weights, root growth rate, water-soluble carbohydrates (WSCs) and starch were evaluated. Bromus valdivianus maintained six live leaves with three leaves growing simultaneously. When an individual tiller started developing its seventh leaf, senescence began for the second leaf (the first relevant leaf for photosynthesis). Plant herbage mass, the root growth rate and tiller growth were maximised at LS-4 onwards. The highest leaf elongation rate, evaluated through the slope of the lamina elongation curve of a fully expanded leaf, was verified at LS-4. The water-soluble carbohydrates (WSCs) increased at LS-5; however, no statistical differences were found in LS-4. The LS-3 and LS-2 treatments showed a detrimental effect on WSCs and regrowth. The leaf photosynthetic rate and stomatal conductance diminished while the leaf age increased. In conclusion, B. valdivianus is a ‘six-leaf’ species with leaf senescence beginning at LS-4.25. Defoliation at LS-4 and LS-5 was optimum for plant regrowth, maximising the aboveground plant parameters and total WSC accumulation. The LS-4 for B. valdivianus was equivalent to LS-3.5 for L. perenne. No differences related to tiller population in B. valdivianus were found in the different defoliation frequencies.

Genotypic variation in water-soluble carbohydrate accumulation in wheat

2006 ◽  
Vol 33 (9) ◽  
pp. 799 ◽  
Author(s):  
Sari A. Ruuska ◽  
Greg J. Rebetzke ◽  
Anthony F. van Herwaarden ◽  
Richard A. Richards ◽  
Neil A. Fettell ◽  
...  
Keyword(s):  
Genotypic Variation ◽  
Dry Weight ◽  
Grain Filling ◽  
Water Soluble ◽  
Soluble Carbohydrates ◽  
Soluble Carbohydrate ◽  
Broad Sense Heritability ◽  
Carbohydrate Accumulation ◽  
Sequential Mechanism ◽  
Water Soluble Carbohydrate

The water-soluble carbohydrate (WSC) that accumulates in the stems of wheat during growth can be an important contributor to grain filling, particularly under conditions when assimilation is limited, such as during end-of-season drought. WSC concentration was measured at anthesis across a diverse set of wheat genotypes over multiple environments. Environmental differences in WSC concentration were large (means for the set ranging between 108 and 203 mg g–1 dry weight), and there were significant and repeatable differences in WSC accumulation among genotypes (means ranging from 112 to 213 mg g–1 dry weight averaged across environments), associated with large broad-sense heritability (H = 0.90 ± 0.12). These results suggest that breeding for high WSC should be possible in wheat. The composition of the WSC, examined in selected genotypes, indicated that the variation in total WSC was attributed mainly to variation in the fructan component, with the other major soluble carbohydrates, sucrose and hexose, varying less. The degree of polymerisation (DP) of fructo-oligosaccharides was up to ~13 in samples where higher levels of WSC were accumulated, owing either to genotype or environment, but the higher DP components (DP > 6) were decreased in samples of lower total WSC. The results are consistent with fructan biosynthesis occurring via a sequential mechanism that is dependent on the availability of sucrose, and differences in WSC contents of genotypes are unlikely to be due to major mechanistic differences.

Time of pruning affects fruit abscission, stem carbohydrates and yield of macadamia

2012 ◽  
Vol 39 (6) ◽  
pp. 481 ◽  
Author(s):  
Lisa McFadyen ◽  
David Robertson ◽  
Margaret Sedgley ◽  
Paul Kristiansen ◽  
Trevor Olesen
Keyword(s):  
Fruit Set ◽  
Photosynthetic Capacity ◽  
Water Soluble ◽  
Soluble Carbohydrates ◽  
Carbon Limitation ◽  
Yield Losses ◽  
Fruit Abscission ◽  
Macadamia Integrifolia ◽  
Water Soluble Carbohydrates ◽  
Stem Water

Macadamia (Macadamia integrifolia Maiden and Betche, M. tetraphylla Johnson and hybrids) orchards in Australia are typically hedged around anthesis (September). Such hedging reduces yields, largely through competition for carbohydrates between early fruit set and the post-pruning vegetative flush, but also through a reduction in photosynthetic capacity caused by the loss of canopy. We examined whether hedging at other times might mitigate yield losses. Hedging time was found to affect yields across four cultivars: ‘A4’, ‘A38’, ‘344’ and ‘816’. Yield losses were lower for trees hedged in November–December than for trees hedged in September. Yields for trees hedged in June were higher than for trees hedged in September in one experiment, but were similar in a second experiment. Yield losses for September and October hedging were similar. Hedging time changed the pattern of fluctuations in stem water-soluble carbohydrates (WSC). WSC declined shortly after hedging in September, October or November, and the declines preceded increases in fruit abscission relative to unpruned control trees. The increase in fruit abscission was less pronounced for the trees hedged in November, consistent with the idea that fruit become less sensitive to carbon limitation as they mature.

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