ASSIMILATE STORAGE IN VEGETATIVE ORGANS OF COCONUT (Cocos nucifera)

2005 ◽  
Vol 41 (2) ◽  
pp. 161-174 ◽  
Author(s):  
I. MIALET-SERRA ◽  
A. CLEMENT ◽  
N. SONDEREGGER ◽  
O. ROUPSARD ◽  
C. JOURDAN ◽  
...  

Assimilate storage in vegetative organs is an essential buffer for the source–sink imbalances that inevitably occur in perennial plants. In contrast to temperate trees, little information is available on such storage in tropical perennials, and almost none for Cocos nucifera. This paper describes the chemical nature, quantity and distribution of carbohydrate reserves in coconut plants grown in an environment favourable to production. The study was carried out on the island of Santo (Republic of Vanuatu, Southern Pacific) on twelve 17-year-old adult plants, representative of a large population, which were felled and characterized for root, trunk and crown dry matter, and contents of soluble sugars and starch. Roots were divided into three diameter classes and distal/proximal portions, the trunk into three axial and three or four radial zones, and the crown into petiole, rachis and leaflets for various leaf ages. The aggregate reserve pool size was compared with estimates of incremental demand for assimilates for growth and fruit production. Plants contained little starch but large quantities of sucrose were found, mainly located in the trunk. Less sucrose was present in roots and little in leaf blades. Large glucose and fructose pools were found in leaves, near the apex of the trunk and in the terminal portions of large roots. Aggregate soluble and non-soluble sugar pools were about equivalent to six months of copra production or 51 days of crop growth. More studies are needed on the dynamics of these sugars to evaluate their physiological role, particularly with regards to stress periods and fluctuating demand for fruit filling.

1999 ◽  
Vol 124 (6) ◽  
pp. 671-675 ◽  
Author(s):  
Xuan Liu ◽  
Paul W. Robinson ◽  
Monica A. Madore ◽  
Guy W. Witney ◽  
Mary Lu Arpaia

Seasonal fluctuations in nonstructural carbohydrates (starch and soluble sugars) were studied in `Hass' avocado (Persea americana Mill.) trees on `Duke 7' rootstock over a 2-year period in southern California. On a dry weight basis, total soluble sugar (TSS) concentrations ranged from 33.0 to 236.0 mg·g-1 dry weight and were high compared to starch concentration (2.0 to 109.0 mg·g-1 dry weight) in all measured organs (stems, leaves, trunks and roots). The seven carbon (C7) sugars, D-mannoheptulose and perseitol, were the dominant soluble sugars detected. The highest starch and TSS concentrations were found in stem tissues, and in stems, a distinct seasonal fluctuation in starch and TSS concentrations was observed. This coincided with vegetative growth flushes over both sampling years. Stem TSS and starch concentrations increased beginning in autumn, with cessation of shoot growth, until midwinter, possibly due to storage of photosynthate produced during the winter photosynthetic period. TSS peaked in midwinter, while starch increased throughout the winter to a maximum level in early spring. A second peak in stem TSS was observed in midsummer following flowering and spring shoot growth. At this time, stem starch concentration also decreased to the lowest level of the year. This complementary cycling between stem TSS and starch suggests that a conversion of starch to sugars occurs to support vegetative growth and flowering, while sugars produced photosynthetically may be allocated directly to support flowering and fruit production.


2020 ◽  
Author(s):  
Xue Wang ◽  
Fei-Hai Yu ◽  
Yong Jiang ◽  
Mai-He Li

Abstract Aims Carbon and nutrient physiology of trees at their upper limits have been extensively studied, but those of shrubs at their upper limits have received much less attention. The aim of this study is to examine the general patterns of non-structural carbohydrates (NSCs), nitrogen (N) and phosphorous (P) in shrubs at the upper limits, and to assess whether such patterns are similar to those in trees at the upper limits. Methods Across Eurasia, we measured the concentrations of soluble sugars, starch, total NSCs, N and P in leaves, branches and fine roots (< 0.5 cm in diameter) of five shrub species growing at both the upper limits and lower elevations in both summer (peak growing season) and winter (dormancy season). Important Findings Neither elevation nor season had significant effects on tissue N and P concentrations, except for lower P concentrations in fine roots in winter than in summer. Total NSCs and soluble sugars in branches were significantly higher in winter than in summer. There were significant interactive effects between elevation and season for total NSCs, starch, soluble sugars and the ratio of soluble sugar to starch in fine roots, showing lower soluble sugars and starch in fine roots at the upper limits than at the lower elevations in winter but not in summer. These results suggest that the carbon physiology of roots in winter may play an important role in determining the upward distribution of shrubs, like that in the alpine tree-line trees.


1986 ◽  
Vol 16 (4) ◽  
pp. 696-700 ◽  
Author(s):  
Chris P. Andersen ◽  
Edward I. Sucoff ◽  
Robert K. Dixon

The influence of root zone temperature on root initiation, root elongation, and soluble sugars in roots and shoots was investigated in a glasshouse using 2-0 red pine (Pinusresinosa Ait.) seedlings lifted from a northern Minnesota nursery. Seedlings were potted in a sandy loam soil and grown in chambers where root systems were maintained at 8, 12, 16, or 20 °C for 27 days; seedling shoots were exposed to ambient glasshouse conditions. Total new root length was positively correlated with soil temperature 14, 20, and 27 days after planting, with significantly more new root growth at 20 °C than at other temperatures. The greatest number of new roots occurred at 16 °C; the least, at 8 °C. Total soluble sugar concentrations in stem tissue decreased slightly as root temperature increased. Sugar concentrations in roots were similar at all temperatures. The results suggest that root elongation is suppressed more than root tip formation when red pine seedlings are exposed to the cool soil temperatures typically found during spring and fall outplanting.


1983 ◽  
Vol 63 (2) ◽  
pp. 415-420 ◽  
Author(s):  
D. G. GREEN

Alfa, a relatively nonhardy alfalfa cultivar continued to accumulate, on a dry weight basis, fructose, α- and β-D-glucose, sucrose and maltose during the latter stages of cold hardening. Rambler, a hardier alfalfa cultivar conversely showed a decrease for these soluble sugars with hardening. Frontier rye, a very hardy winter habit cereal showed decreases in these soluble sugars plus melibiose during the same hardening period. These results support the hypothesis that hardy cereals and alfalfa undergo a decrease in soluble sugars with hardening, while less hardy cereals and alfalfa continue to increase in content of soluble sugars. Manitou wheat appeared not to fit this hypothesis and showed the decreased soluble sugars usually associated with hardy cultivars. Although Manitou is a spring type wheat, one of its parents, Thatcher, does contain gene(s) for the winter habit.Key words: Sugar, cold hardening, wheat, rye, alfalfa


2021 ◽  
Author(s):  
Lynn Doran ◽  
Amanda P. De Souza

Quantification of total soluble sugars (as glucose) in plant tissue extracts via the sulfuric phenol method adapted for 96 well plates.


2003 ◽  
Vol 60 (2) ◽  
pp. 239-244 ◽  
Author(s):  
José Carlos da Silva ◽  
José Donizeti Alves ◽  
Amauri Alves de Alvarenga ◽  
Marcelo Murad Magalhães ◽  
Dárlan Einstein do Livramento ◽  
...  

One management practice of which the efficiency has not yet been scientifically tested is spraying coffee plants with diluted sucrose solutions as a source of carbon for the plant. This paper evaluates the effect of foliar spraying with sugar on the endogenous level of carbohydrates and on the activities of invertase and sucrose synthase in coffee (Coffea arabica L.) seedlings with reduced (low) and high (normal) levels of carbon reserve. The concentrations used were 0.5 and 1.0% sucrose, and water as a control. The use of sucrose at 1.0% caused an increase in the concentration of total soluble sugars in depauperate plants, as well as increased the activity of the following enzymes: cell wall and vacuole acid invertase, neutral cytosol invertase and sucrose synthase. In plants with high level of carbon reserve, no increments in total soluble sugar levels or in enzymatic activity were observed. Regardless of treatments or plants physiological state, no differences in transpiration or stomatal conductance were observed, demonstrating the stomatal control of transpiration. Photosynthesis was stimulated with the use of 0.5 and 1.0 % sucrose only in depauperate plants. Coffee seedling spraying with sucrose is only efficient for depauperate plants, at the concentration of 1.0%.


2010 ◽  
Vol 40 (4) ◽  
pp. 781-786 ◽  
Author(s):  
Fábio Luiz Partelli ◽  
Henrique Duarte Vieira ◽  
Ana Paula Dias Rodrigues ◽  
Isabel Pais ◽  
Eliemar Campostrini ◽  
...  

The present research aimed to characterize some biochemical responses of Coffea canephora (clones 02 and 153) and C. arabica (Catucaí IPR 102) genotypes subjected to low positive temperatures, helping to elucidate the mechanisms involved in cold tolerance. For that, one year old plants were subjected successively to 1) a temperature decrease (0.5°C a day) from 25/20°C to 13/8°C (acclimation period), 2) a three day chilling cycle (3x13/4°C) and to 3) a recovery period of 14 days (25/20°C). In Catucaí (less cold sensitive when compared to clone 02) there was an increased activity in the respiratory enzymes malate dehydrogenase and pyruvate kinase. Furthermore, Catucaí showed significant increases along the cold imposition and the higher absolute values after chilling exposure of the soluble sugars (sucrose, glucose, fructose, raffinose, arabinose and mannitol) that are frequently involved in osmoregulation and membrane stabilization/protection. The analysis of respiratory enzymes and of soluble sugar balance may give valuable information about the cold acclimation/tolerance mechanisms, contributing to a correct selection and breeding of Coffea sp. genotypes.


2017 ◽  
Vol 27 (3) ◽  
pp. 206-216 ◽  
Author(s):  
Juliana F. Santos ◽  
Lynnette M.A. Dirk ◽  
A. Bruce Downie ◽  
Mauricio F.G. Sanches ◽  
Roberval D. Vieira

AbstractObtaining corn hybrid seeds (Zea mays L.) with high vigour depends on the parental lines and the direction of the cross, and this relates to seed desiccation tolerance and composition. This research studied reciprocal crosses between pairs of proprietary, elite parent lines (L1 and L5; L2 and L4) producing hybrid seeds with different qualities attempting to correlate vigour with seed composition, focusing on storage proteins, starch and soluble sugar amounts. Four corn hybrid seed lots produced from reciprocal crosses were compared (HS 15 with HS 51, and HS 24 with HS 42) by assessing germination, vigour, and seedling emergence in the field. Seed composition was assessed in mature, dehydrated seeds. Proteins were extracted, quantified, and analysed by electrophoresis and densitometry. Starch amounts were assessed using a kit and soluble sugars were determined using high performance liquid chromatography with pulsed electrochemical detection. The L1 and L2 lineages, used as female parents, provided seeds with lower vigour; however, the quantification of major protein bands, and sucrose, raffinose and stachyose were similar between seed lot pairs. While both total seed protein and starch varied between reciprocal hybrids for one of the two sets of crosses, the amounts of neither correlated with seed vigour. Interestingly, hybrids with low seed vigour (HS 15, HS 24) accumulated greater amounts of fructose relative to their reciprocal; correlation analysis confirmed these results. We demonstrate different effects on seed vigour dependent on the maternal parent in reciprocal crosses producing hybrid corn seeds. We also show that vigour is negatively correlated with seed reducing sugar contents.


2008 ◽  
Vol 32 (1) ◽  
pp. 19-25 ◽  
Author(s):  
Renata Braga Souza Lima ◽  
José Francisco de Carvalho Gonçalves ◽  
Silvana Cristina Pando ◽  
Andréia Varmes Fernandes ◽  
André Luis Wendt dos Santos

This study aimed to characterize protein, oil, starch and soluble sugar mobilization as well as the activity of alpha-amylase during rosewood seed germination. Germination test was carried out at 25°C and the following parameters were analyzed: percentage of germination, initial, average, and final germination time. Seed reserve quantification was monitored in quiescent seeds and during different stages of radicle growth. Starch mobilization was studied in function of a-amylase activity. Germination reached 87.5% at the initial, average, and final time of 16, 21 and 30 days, respectively. Oil mobilization showed a negative linear behavior, decreasing 40% between the first and the last stage analyzed, whereas protein levels increased 34.7% during the initial period of germination. Starch content (46.4%) was the highest among those of the metabolites analyzed and starch mobilization occurred inversely to the observed for soluble sugars; alpha-amylase activity increased until the 15th day, a period before radicle emission and corresponding to the highest starch mobilization. The high percentage of rosewood seed germination may be related to the controlled condition used in the germination chamber as well as to high seed reserve mobilization, in special oil and starch.


Author(s):  
Dinesh Kumar ◽  
Mohamad Al Hassan ◽  
Oscar Vicente ◽  
Veena Agrawal ◽  
Monica Boscaiu

Elucidating the mechanisms of abiotic stress tolerance in different species will help to develop more resistant plant varieties, contributing to improve agricultural production in a climate change scenario. Basic responses to salt stress, dependent on osmolyte accumulation and activation of antioxidant systems, have been studied in Nerium oleander, a xerophytic species widely used as ornamental. Salt strongly inhibited growth, but the plants survived one-month treatments with quite high NaCl concentrations, up to 800 mM, indicating the the species is relatively resistant to salt stress, in addition to drought. Levels of proline, glycine betaine and soluble sugars increased only slightly in the presence of salt; however, soluble sugar absolute contents were much higher than those of the other osmolytes, suggesting a functional role of these compounds in osmotic adjustment, and the presence of constitutive mechanisms of response to salt stress. High salinity generated oxidative stress in the plants, as shown by the increase of malondialdehyde levels. Antioxidant systems, enzymatic and non-enzymatic, are generally activated in response to salt stress; in oleander, they do not seem to include total phenolics or flavonoids, antioxidant compounds which did not accumulate significantly in salt-trated plants


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