Sugar Beet Storage Root Research Articles

Workflow for phenotyping sugar beet roots by automated evaluation of cell characteristics and tissue arrangement using digital image processing

BackgroundCell characteristics, including cell type, size, shape, packing, cell-to-cell-adhesion, intercellular space, and cell wall thickness, influence the physical characteristics of plant tissues. Genotypic differences were found concerning damage susceptibility related to beet texture for sugar beet (Beta vulgaris). Sugar beet storage roots are characterized by heterogeneous tissue with several cambium rings surrounded by small-celled vascular tissue and big-celled sugar-storing parenchyma between the rings. This study presents a procedure for phenotyping heterogeneous tissues like beetroots by imaging.ResultsTen Beta genotypes (nine sugar beet and one fodder beet) were included to establish a pipeline for the automated histologic evaluation of cell characteristics and tissue arrangement using digital image processing written in the programming language R. The identification of cells has been validated by comparison with manual cell identification. Cells are reliably discriminated from intercellular spaces, and cells with similar morphological features are assigned to biological tissue types.ConclusionsGenotypic differences in cell diameter and cell arrangement can straightforwardly be phenotyped by the presented workflow. The presented routine can further identify genotypic differences in cell diameter and cell arrangement during early growth stages and between sugar storage capabilities.

Reakcja buraka cukrowego na substancje humusowe i dolistne nawożenie potasem

Sugar beet (Beta vulgaris L.) requires fertile soils with high biological activity, rich in minerals and organic nutrients. Biological properties of soil, such as enzymatic and microbial activity, can be effectively improved through the application of humic substances. This enables an increase in growth dynamics and, consequently, in the yield. The aim of this study was to assess sugar beet germination, depending on the soil application of the humic preparation Humistar (12% of humic acids, 3% of fulvic acids) as well as to assess the yield of sugar beet storage roots and the content of sugar in these storage roots, depending on soil applications of Humistar and/or foliar application of potassium fertilizer Drakar (31% K2O, 3% N). The field experiment was conducted in the soil classified as Mesic Typic Hapludalfs. Soil application of Humistar contributed to a reduction in sugar beet germination, measured as % of plants germinated within 14 days after sowing. However, the growth of plants in soil with Humistar was more intensive than in the control. A significant, positive influence of Humistar and Drakar on the yield of sugar beet roots has been found. Application of the two treatments did not produce better results than the use of each of them separately. Sugar content in roots was not affected by experimental factor. The study showed that both soil application of humic substances and the use of foliar potassium fertilizer can improve the yield of sugar beet and, consequently, increase the biological yield of sugar from storage roots.

Effects of free air CO2 enrichment on root growth of barley, sugar beet and wheat grown in a rotation under different nitrogen supply

Elevated atmospheric CO2 concentrations [CO2] are known to change plant growth by stimulation of C3 photosynthesis and by reduction of transpiration of both C3 and C4 crops. In comparison to the information on above ground plant responses only limited knowledge exists on the response of root growth of arable crops to elevated [CO2] which is particularly true for temperate crop species under real field conditions. A free air CO2 enrichment (FACE) study (550ppm at daylight hours) was carried out in a crop rotation of winter barley, sugar beet and winter wheat repeated twice in the course of six years on a sandy loam soil at Braunschweig, Northern Germany. Winter barley and sugar beet were included for the first time in a FACE study. A possible interaction with restricted nitrogen (N) supply was studied by fertilizing the CO2 treatment plots with adequate and 50% of adequate N supply. Fine root samples were taken in the plough layer and below at 3–4 sampling dates during the vegetation period and root dry matter (excluding sugar beet storage root), shoot root ratio, root length density, specific root length and root tissue composition (CN ratio) were determined. Main effects of elevated [CO2] on the investigated variables were slightly significant. Significant CO2 effects were observed in interaction with the sampling date. In most cases elevated [CO2] increased root dry matter early in the vegetation period with a maximum growth stimulation of up to 54% as compared to ambient [CO2]. Concomitantly, root length densities were increased in both winter wheat and sugar beet. For winter barley also a significant decrease in root dry weight and significant increase of shoot root ratio was detected at final harvest while such an effect was not significant for sugar beet. Specific root length as an indicator of root morphology was mainly influenced by crop species. As a result, there was no consistent overall effect of elevated [CO2] on biomass partitioning in this study as changes in shoot root ratio only occurred at specific sampling dates indicating a similar stimulation of roots and above-ground biomass due to elevated [CO2]. Nitrogen supply did not alter the effect of elevated [CO2] on any of the root variables apart from CN ratios. A significant increase of root CN ratios in wheat and sugar beet was observed under elevated [CO2], but this effect was much smaller than the effect of N supply.

Carbohydrate remobilization from storage root to leaves after a stress release in sugar beet (Beta vulgaris L.): experimental and modelling approaches

SUMMARYCarbohydrate remobilization from the sugar beet storage root to support leaf regrowth after release from water stress was demonstrated by experimental and modelling approaches. Experimental trials were carried out in northern France in 1994 and 1995 and in southern France in 2005, in conditions that involved a succession of soil moisture stresses and re-hydrations. Drought stress slowed leaf growth and the subsequent release of stress resulted in regrowth. A second trial showed that after total defoliation, sugar beet was able to produce new leaves. It was assumed that this leaf renewal, observed at drought stress release or after defoliation, relied on the possibility of remobilizing carbohydrates from storage roots to above-ground organs. This assumption was tested through a heuristic modelling approach, involving the STICS crop model and its existing sub-model on remobilization. The relevance of these formalizations for sugar beet was tested on the experimental data to validate the plant behaviour concerning remobilization. The model succeeded in reproducing leaf area index (LAI) dynamic trends and particularly leaf re-growth after drought stress release or defoliation, despite an over-estimation of the drought stress effect involving an inaccurate simulation of the changes in LAI. Nevertheless, the model's ability to forecast accurately above-ground and storage root dry weight, as well as trends in LAI dynamics, showed that the assumptions made about remobilization were able to explain sugar beet behaviour.

Proline content of sugar beet storage roots: Response to water deficit and nitrogen fertilization at field conditions

Drought stress is one of the major factors causing profit loss of the sugar beet crop. The accumulation of proline, an indicator of water stress, has been reported in response to osmotic and salt stress in sugar beet leaves, but there is little information about its levels in storage roots. Proline in storage roots is potentially useful as indicator of situations that lead to decreased yield and quality of the root, such as drought stress and excess nitrogen. This study has been focused towards proline quantification in storage roots from field trials concerning irrigation, sugar beet variety and nitrogen fertilization. Water deficit is the main factor leading to proline accumulation in sugar beet roots. Excess N supply also increases proline levels, partially by increasing leaf area index (LAI) and exacerbating drought stress. The two varieties studied (Claudia and Ramona) had different responses to water shortage and to nitrogen. Maximum proline levels were measured in Claudia roots subjected to a combination of water shortage and excess N. A positive and significant correlation was found between proline and glucose levels in sugar beet roots, pointing to a relationship between stress responses, carbohydrate catabolism, and proline and glucose accumulation. This proposal was supported by the effect of treatments with di-1- p-menthene (anti-transpirant) and with DMDP (2,5-dihydroxymethyl-3,4-dihydroxypyrrolidina, a glycosidase inhibitor), which lead to decreased level of proline in non-irrigated Claudia sugar beet roots.

Radial and axial water transport in the sugar beet storage root

To evaluate the contribution of transcellular, apoplastic and symplastic pathways to water movements, horizontal (axial pathway) and vertical (radial pathway) sugar beet root (Beta vulgaris L.) slices were studied. Volume flows (J v ) were measured under hydrostatic and/or osmotic gradients, using a computer-based data-acquisition system. When tissues were tested under hydrostatic gradients (0.3 MPa m -1 ) a much more important permeability was observed in the axial pathway, as compared with the radial one. Negative pressure gradients (tensions) were as effective as positive ones in inducing a net water movement. After the establishment of a concentration gradient in the radial pathway (obtained by adding 300 M m -3 mannitol to the employed solution) an osmotic flux, sensitive to HgCl 2 , was observed. The inhibitory effect of mercurial compounds was reversed by β-mercaptoethanol while [ 14 C] mannitol unidirectional fluxes were not affected by mercurial agents. In the axial pathway, the presence of a mannitol gradient did not develop a sustained osmotic flux. After an initial J v in the expected direction, the J v reversed and moved in the opposite way. It is concluded that, in the sugar beet root, water channels play a significant role in water transfers in the radial pathway. On the other side, water and solutes are transported by a hydrostatic gradient in the xylem vessels. In general, these results extend and adapt to a storage root the 'composite transport model' first proposed by Steudle et al.

Radial and axial water transport in the sugar beet storage root

Radial and axial water transport in the sugar beet storage root

Identification of a sucrose nonfermenting-1-related protein kinase in sugar beet (Beta vulgaris L.)

A 154 bp polymerase chain reaction product, SBKIN154, showing 76–83% sequence identity with sucrose nonfermenting-1 (SNF1)-related protein kinase nucleotide sequences from other plant species was amplified from sugar beet storage root RNA. Southern blot analysis using SBKIN154 as a hybridisation probe suggested that sugar beet contains either a single-copy SNF1-related gene or a small gene family of highly conserved genes. An antibody raised to a heterologously-expressed fusion of the rye SNF1-related protein kinase, RKIN1, and maltose binding protein, recognised a protein of the expected size (Mr approx. 60,000) on western blots of storage root, stalk, leaf and root extracts. Measurements of SNF1-related activity were made using a specific peptide (SAMS) phosphorylation assay. Activity was highest (0.38 nmol min-1 mg-1 protein) in developing storage roots and lowest (0.035 nmol min-1 mg-1) in fibrous roots.

Differential effects of turgor on sucrose and potassium transport at the tonoplast and plasma membrane of sugar beet storage root tissue

ABSTRACTWhen turgor was increased, by decreasing the concentration of mannitol bathing discs of sugar beet storage root tissue, the rates of sucrose and potassium uptake into the vacuole were decreased. At all external mannitol concentrations the rate of sucrose and potassium uptake across the plasma membrane was an order of magnitude greater than the rate of quasi‐steady uptake into the vacuole, implying a very large efflux. Efflux of both sucrose and potassium was increased at high turgor. However, while increasing turgor decreased the rate of K+ uptake, the rate of sucrose uptake at the plasma membrane increased with time. Compartmental analysis of tracer exchange kinetics was used to determine unidirectional K+ fluxes. From these results, it was estimated that the increase in K+ efflux accompanying a 1.5 MPa increase in turgor could lead to a net increase of 140mol−3h−1 in the external potassium concentration. It is suggested that the turgor‐imposed increase in solute efflux is a means of regulating intracellular osmotic pressure and/or turgor in sugar beet storage roots, but that sucrose is preferentially retrieved from the apoplast, even under conditions of excessively high turgor. However, much of this sucrose is probably lost from the cell, implying a ‘futile’ sucrose transport cycle at the plasma membrane. The turgor‐stimulated leak of potassium could play a major role in the regulation of turgor pressure in sugar beet storage root tissue.

Sulphate supply and its effects on sap quality during growth in sugar beet storage roots

AbstractIncreasing the concentration of inorganic N increases the concentration of α‐amino‐N compounds in roots of hydroponically‐grown sugar beet plants. These concentrations can, however, be reduced by increasing the concentration of sulphate in the nutrient solution.

Binding of Glycolytic Enzymes to a Particulate Fraction in Carrot and Sugar Beet Storage Roots

Numerous studies have demonstrated a rapid increase in the respiration rate during aging of slices of tuber and storage roots. To determine the molecular mechanisms of this phenomenon, the role of enzyme binding to the subcellular particulate fraction has been assessed in carrot (Daucus carota L.) and sugar beet (Beta vulgaris L.). Soluble versus particulate fractions were separated by centrifugation at 16,000g and both fractions assayed for the activities of six glycolytic enzymes. Preparations from sliced and aged tissues showed elevated percentages of five enzymes associated with the particulate fraction as compared with controls. The stimulation of respiration which occurs during aging of underground storage organ slices may result, in part, from an association of enzymes with the particulate fraction of the cell promoting an elevated glycolytic rate.

Opportunities for regulation of sugar beet storage root growth

The percentage of sucrose in sugar beet storage root fresh and dry matter is closely related to root structure. It has been suggested that the sucrose content might be increased by using plant growth regulators to modify storage root structure through control of cambial development, cell division and cell expansion. During storage root development correlations were found between the changing phytohormone profiles and the formation of secondary cambia and their subsequent cell division and expansion. Sugar beet root derived cell suspension cultures were used for detailed studies of the roles of endogenous phytohormones. The gibberellin synthesis inhibitor paclobutrazol was tested in cell cultures and whole plants. The observations provide a basis for development of plant growth regulator regimes to optimise sucrose yield from sugar beet.

Pectolytic enzyme production by Phoma betae

Phoma betae from decayed sugar beet storage root tissue grew most rapidly in culture at 15C but produced more polygalacturonase (PG) at 20C. When the fungus was supplied with six different nitrogen sources, it produced the most PG on (NH4)2SO4.Assays of dialyzed culture filtrates using sodium polypectate and pectin or cell wall material from storage roots as the carbon sources showed the production of exopolygalacturonase (exo-PG) and endopolygalacturonate trans-eliminase (endo-PGTE). No pectin methyl esterase was detected. Exo-PG and endo-PGTE also were present in decayed sugar beet tissue. Only endo-PGTE was detected within 3 mm of tissue surrounding the rotted area.In culture, cell wall material from the susceptible variety A58 induced more endo-PGTE formation than the resistant 2B. But 2B induced more exo-PG formation than A58. It is suggested that endo-PGTE plays a major role in cell wall degradation because pH 7.5 was optimum for tissue maceration and pH 8.5 for enzyme activity and the advancing margins of rotted tissue contained only endo-PGTE.