Aspects of carbohydrates dynamics directly changed by the factors

Total Non-Structural Carbohydrates (TNC) seasonal dynamics based on the relationship with leaf-fruit ratio were quantified at within a period of five years at varied phonological stages of grapevine in one year old and two year old roots, trunks, and canes that belonged to the cultivar ‘Chasselas.’ Carbohydrates storage was in the form of starch in varied localities of the grapevine during the growth season.

 A small portion (less than 7% of the dry weight) of the total non-structural carbohydrates represented soluble carbohydrates. In the trunks and roots, there was fluctuation of starch content during the season of growing, attaining the lowest figures between flowering and bud breaking in relation to the year while the highest values were recorded between leaf fall and harvest.

Aspects of carbohydrates dynamics directly changed by the factors

The content of soluble sugar in the two-year canes and the trunks increased with a decreased in temperature in the winter period. Negative correlation existed between the values of the average temperature of the air that was recorded within the seven days before samples for carbohydrates analysis were collected, and the content of soluble carbohydrates in the canes that were two years old and the trunks. The ratio of leaf to fruit (source-sink) greatly influenced the concentration of TNC, starch in roots and trunks during harvest, and the content of sugar in berries. Higher ratio of leaf to fruits led to an increase in the concentration of TNC and starch in roots and trunks. Leaf area and canopy height did not have significant influence on the content of TNC, starch, or soluble sugars in permanent parts of the vine. 

Literature Review

Sources of Processes/components altered

Carbohydrates manufactured by the leaves have varied roles. The roles include forming support structures like gluco-protein and hemi-cellulose, storage of energy and forming the building blocks for organic compounds. Carbohydrates storage in plants can be temporary as in the case of where it is stored in the leaves during the day and used at night or for longer periods as in the case of roots, trunks, and canes. TNC in wood fractions and roots of grapevines play significant roles in the quality potential and longevity of the wine at harvest (Matese et.al 2015)

 TNC also protects from frost, take part in fruit growth, flower induction, and leaf development. TNC seasonal vibrational studies in roots, trunks, and canes provided the basis for analysis of TNC dynamics for insoluble and soluble carbohydrates including their distribution between sink and source organs. Other studies showed that grape variety, canopy management, crop load, water restriction, and climate influenced TNC reserves and C assimilation especially in the permanent regions.

The management of canopy, including defoliation and shoot topping also affects TNC allocation and reserves by altering the ratio of the source sink. Other studies demonstrated that grapevines that produced higher yields greatly depended on the period of post-harvest to replenish the reserves of the TNC more particularly in the roots. It has been demonstrated that under climatic conditions that are cool, minimum ration of leaf to fruit approaching 10-20cm area of leaf/g fruit or 1-1.4 m² light exposed leaf area per kg of fruit is necessary for achieving enough grape maturation. TNC reserves also play significant roles in abiotic and biotic stress defense, reproductive and vegetative growth, and energy requirements (Ruml et.al 2012)  

Literature Review

In analyzing the seasonal changes of the reserves of TNC in different grapevine parts (woody fractions and roots) and charactering the source sink ratio influence, an experiment was carried out in the mature grapevine fields of ‘Chasselas’ with varied ratio of leaf to fruit. The difference in the ratio of leaf to fruit was achieved by manipulating the crop load and canopy height. The seasonal changes of the reserves of the TNC were observed in the course of five consecutive years with the view of bringing out the intra and inter-annual storage and mobilization of grapevine TNC. The effects of the ratio of leaf to fruit on the content of TNC in the permanent grapevine regions at harvest were also studied.

Materials and Methods

The site of study and plant materials

The study was carried out in the course of 1998 and 2002 and involved Vitis vinifera L. (Chasselas). The station of the research was Agroscope Changes-Wadenswil, in the vineyard of experiment of Pully in Switzerland. The orientation of the plot was south within a slope of 10-20%. The pruning of the vines was done vertically along the shoot (cane pruning). Six shoots for every vine was pruned.

Comparison was made between two planting fields of 4900 vines per hectors and 9800 vines per hectors each having the heights of their canopies at 0.75m and 1.25m. The height of the trunk (6m) was the same for the two fields. The soil characteristics of the Pully vineyard are deep and fertile. The capacity of the soil to hold water is very high at more than 200mm on a depth of soil that is 2m. The weather station found at the field of study provided data on the climatic conditions.

The ratio of leaf to fruit was manipulated in two ways. First, it was done by varying the heights of the canopy where the heights of the two canopies (at 0.75m and 1.25m.) were kept constant by continues topping. First topping was done at the end of flowering on day of the year while re-topping of the shoots was done after every three weeks. Secondly, manipulation was done through yield variation (Fraga et.al 2012)

Measurement of leaf area

Non-destructive determination of leaf area was conducted several times during the season of growing between 1998 and 2000. This was done by estimating the length of the lamina of each leaf. The obtained lengths were changed to areas based on allometric equations made from the measurement of direct areas of the leaves that were previously harvested. All lateral and primary leaves on two shoots in every vineyard were estimated to obtain the average area of each leaf per shoot. The average area of shoot leaf was used to determine total area of vine leaf through multiplication with the shoot number per vine. Carbonneau’s method was used to estimate the area of leaf that was exposed to saturated light. 

Results

Seasonal TNC dynamics of the soluble sucrose that includes fructose, glucose and sucrose together with the insoluble glucose that includes starch are found in various parts of the plants. They also reveal most of the forms in which these food components are stored. There is a slight variation in the amount of sugar in the roots. This could be on the end of 3% in the specific seasons. The fluctuation of the starch in the season was between 12% and 20%.In the subsequent years there was increase progressively in the content of the starch just before flowering could pick up (Bellon et.al 2016).

Sources of Processes/components altered

 This value however increased further as the process of flowering picked up besides veraison. The starch accumulation in the roots continued in the harvest season until the leaf fall. Just before bud break, there was a decrease in the accumulation of the starch in the roots. In some cases this process lasted up to the point flowering began. In the trunks and canes, the dominant form of storage was starch especially during the season of growth. This concentration however wads low as compared to the concentration in the roots (Villanueva et.al 2014).

The changing of the starch into other forms of carbohydrates was very evident in the periods of winter. This coincided with the periods of the lower temperatures. The level of the starch was seen to be lowest in the periods of the flowering especially in the two year old wood of the cane. The concentration of the soluble solution increased from 2-3% that is 300 during the period of the leaf fall and 60 during the period of the seed dormancy.

 There was an established correlation between the soluble sugar concentration in the trunks and canes and the air temperature. The maximum concentration of sugar in the tissues was measured at the lowest temperatures. The maximum reserve in the TNC was at the point of leaf fall on the parts of the vine and the minimum reserves were just before the flowering process began.

When the influence of the leaf-fruit ratio was checked, the vines were found to have maintained o.75 capacity height. The leaf area was found to be at 2.5m2 from the flowering end. The vines that were at an average height of 1.25m tall and the area was at 4.4m2.It was found the three was no impact on the TNC by the leaf area or the height of the canopy (Molitor et.al 2014)

These same results were found in the trunks of a cane one or two years old. In the trunks and the roots that were 0.75 m, the content of the TN was found to be lower in the period of winter. The leaf fruit ratio had Avery big impact on the berry sugar content at the period of harvest .There was no significant change or impact on the leaf fall. The results indicated that the highest TNC values were at the point when leaf fruit ratio was at 2.0m2kg.Since the TNC is generated mainly from the starch, similar results were obtained in the starch content in the roots and in the trunks (Mikulic et.al 2012).

Discussions

The dynamics of the seasonal TNC indicates that stored carbohydrates in the forms of the starch in the roots and the trunks in the cane wood are very variasble. The percentage of the soluble carbohydrates was found to be less than 7%.These particular results confirm that the earlier observations were actually different. In the trunks the starch was converted into the sugars that were seen soluble during winter seasons especially for those canes older than one year. This will greatly improve the frost wood resistance (Costa et.al 2016)

Materials and Methods

 Since the starch is known is known to be osmotic ally inactive, it cannot improve the frost resistance by it. In order for the grapevine acclimatization to take place, there has to be conversion of the starch. The increase of the starch could be attributed to the assimilation from sugar that was related to increase in the ambient just before the period of the bud break. This was to replenish the starch used for the maintenance during the respiration. After the bud burst, the content of the starch increased to the maximum level at the cluster. In the trunks, the accumulation of the starch was up to the point of the harvest.

What was considered important at the end of the season was accumulation of the starch in the roots and the woody parts of the sample (Matese & Di Gennaro 2015). This result could be attributed to the lower rainfall and higher radiations. These favorable climatic conditions could not be maintained. In the leaf fall ratio study, the source sink relation was expressed as the ratio of the part of the leaves exposed to light to the other part of the leaf that is influenced by the light TNC.

The content of the TNC greatly diminished in the roots when the leaf fall was recorded low especially below 1.5m2kg.In addition the studies have shown that high yields of the grapevine was obtained and it was entirely dependent on the climatic conditions in the period of post-harvest. In the cases of the cool climate conditions but with water restrictions, there was a registered powerful sink in the dynamics of the TNC (Comuzz et.al 2013).

Impacts of the environmental factor

The grapevines with the high number of leaves had the least accumulation of the starch. The stimulation of the leaf with greater accumulation of the starch became inhibited. The vegetative growth in these leaves was taking place at the expense of the secondary roots. The results and quantity of the TNC were similar in the two canopy or quantities. The other explanation to this could be the effects of translocation. The translocation of the sugars from the starch mobilization that takes place in the roots and the fractions of the woody sections to the berries during the period of ripening (Trouvelot et.al 2015)

This process only takes place in the periods when the weather conditions are not very favorable. These kinds of weather include the low solar radiations and high precipitations. The results that were used in this particular investigation were obtained from a grapevine that had been thoroughly watered, having favorable vegetative growth and a lot of vigor in the growth. The impacts of the restriction of water represented a major section of feature in the accumulation of sugars. The TNC accumulation and allocations in the different sink was as a result of these effects. In order to establish the future results, the effects of water on the development of TNC must be uncovered (Koufos et.al 2014)

Conclusion

The grapevine only stores non-structural carbohydrates that mainly constitutes starch but in the different parts of the plant. There was very important mobilization of the starch from the parts such as roots and the trunks that was observed from the period of the budburst and flowering. This was father related to the reduction in the reserves of TNC in the same organs (Brice 2014) the lowest values were taken in the roots and trunks during the periods of the flowering.

Measurement of leaf area

From the period of flowering there was progressive accumulation of the starch in the woody parts of the cane. The highest level of the TNC value was obtained at the period of the harvest and in some cases after the period of the leaf fall. At the end of the season, the starch content in the roots was found to be higher in the years when the environmental conditions were favorable. The content of the fruit was doubled from 12% to almost 25% in the very year. Similarly, the relationship between the carbohydrates that were soluble and those that are generated from the conversion of the starch was perfectly established.

References

Bellon-Maurel V, Peters GM, Clermidy S, Frizarin G, Sinfort C, Ojeda H., … & Short, MD. 2015. Streamlining life cycle inventory data generation in agriculture using traceability data and information and communication technologies–part II: application to viticulture. Journal of cleaner production, 87, 119-129.

Brice J. 2014. Attending to grape vines: perceptual practices, planty agencies and multiple temporalities in Australian viticulture. Social & Cultural Geography, 15(8), 942-965.

Comuzzo P, Rauhut D, Werner M, Lagazio C, & Zironi R. 2013. A survey on wines from organic viticulture from different European countries. Food Control, 34(2), 274-282.

Costa JM, Vaz M, Escalona J, Egipto R, Lopes C, Medrano H, & Chaves MM. 2016. Modern viticulture in southern Europe: vulnerabilities and strategies for adaptation to water scarcity. Agricultural Water Management, 164, 5-18.

Fraga H, Malheiro AC, Moutinho?Pereira J & Santos JA. 2012. An overview of climate change impacts on European viticulture. Food and Energy Security, 1(2), 94-110.

Koufos G, Mavromatis T, Koundouras S, Fyllas NM. & Jones GV. (2014). Viticulture–climate relationships in Greece: the impacts of recent climate trends on harvest date variation. International Journal of Climatology, 34(5), 1445-1459.

Matese A & Di Gennaro SF. 2015. Technology in precision viticulture: A state of the art review. International Journal of Wine Research, 7, 69-81.

Matese A, Toscano P, Di Gennaro SF, Genesio L, Vaccari FP, Primicerio J, … & Gioli B. 2015. Intercomparison of UAV, aircraft and satellite remote sensing platforms for precision viticulture. Remote Sensing, 7(3), 2971-2990.

Mikulic?Petkovsek M, Schmitzer V, Slatnar A, Stampar F, & Veberic R. 2012. Composition of sugars, organic acids, and total phenolics in 25 wild or cultivated berry species. Journal of food science, 77(10), C1064-C1070.

Molitor D, Caffarra A, Sinigoj P, Pertot I, Hoffmann L, & Junk J. 2014. Late frost damage risk for viticulture under future climate conditions: a case study for the L uxembourgish winegrowing region. Australian Journal of Grape and Wine Research, 20(1), 160-168.

Ruml, M., Vukovi?, A., Vujadinovi?, M., Djurdjevi?, V., Rankovi?-Vasi?, Z., Atanackovi?, Z., … & Petrovi?, N. 2012. On the use of regional climate models: implications of climate change for viticulture in Serbia. Agricultural and forest meteorology, 158, 53-62.

Trouvelot S, Bonneau L, Redecker D, Van Tuinen D, Adrian M, & Wipf D. 2015. Arbuscular mycorrhiza symbiosis in viticulture: a review. Agronomy for sustainable development, 35(4), 1449-1467.

Villanueva-Rey P, Vázquez-Rowe I, Moreira MT, & Feijoo G. 2014. Comparative life cycle assessment in the wine sector: biodynamic vs. conventional viticulture activities in NW Spain. Journal of Cleaner Production, 65, 330-341.