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71.
72.
L. J. Dallagnol F. A. Rodrigues A. R. M. Chaves F. X. R. Vale F. M. DaMatta 《Plant pathology》2013,62(1):120-129
The effect of soluble silicon (Si) on photosynthetic parameters and soluble sugar concentrations was determined in leaves of rice cv. Oochikara and mutant plants of Oochikara defective in active Si uptake [low silicon 1 (lsi1)]. Plants were grown in hydroponic culture amended with 0 (?Si) or 2 mm Si (+Si), under either low or high photon flux density (PFD) and with or without inoculation with Bipolaris oryzae, the causal agent of brown spot of rice. Leaf Si concentration increased by 141 and 435% in +Si cv. Oochikara and by 119 and 251% in +Si lsi1 mutant plants under high and low PFD, respectively, compared with ?Si plants. Plant biomass accumulation was improved by Si regardless of PFD, especially plants for cv. Oochikara. Brown spot severity was highest in ?Si plants for cv. Oochikara and lsi1 mutant plants under low PFD. In the presence of Si, disease severity in plants grown under both low and high PFD was reduced, except for lsi1 mutant plants under high PFD. Plant inoculation reduced the photosynthetic parameters measured regardless of plant material or Si supply. A decrease of net carbon assimilation rate (A) of inoculated plants under low PFD compared with non‐inoculated plants was associated with damage in the photosynthetic apparatus, except for +Si cv. Oochikara in which stomatal restriction [low water vapour conductance (gs)] contributed to A reduction. Under high PFD, damage to the photosynthetic apparatus of inoculated plants was the main reason for the reduction in A for +Si and ?Si lsi1 mutant plants. In addition, for ?Si cv. Oochikara, a reduction in gs contributed to reduced A. However, for +Si cv. Oochikara, gs was the limiting factor for A. Inoculated plants of +Si cv. Oochikara had higher A values than +Si lsi1 mutant plants, regardless of environmental conditions. Soluble sugars were not detected in leaf tissues of plants under low PFD. For high PFD, Si improved the hexose concentration in non‐inoculated plants at 144 h after inoculation (hai) for lsi1 mutant plants and from 96 hai onwards for cv. Oochikara compared with ?Si plants. However, plant inoculation reduced hexose concentration compared with non‐inoculated plants, mainly in +Si plants, regardless of plant material. Sucrose concentration increased in leaves of cv. Oochikara in the presence of Si whether inoculated or not. For +Si lsi1 mutant plants, sucrose concentration increased only at 48 hai compared with ?Si plants, whether inoculated or not. The results of this study show that a minimum Si concentration is needed in leaf tissues of rice plants to avoid the negative impact of B. oryzae infection on photosynthesis and sugar concentration. High leaf Si concentration resulted in an increased soluble sugar concentration and together, but in independent ways, soluble sugar and Si reduced brown spot severity of rice. 相似文献
73.
Summary In measuring fructose 1,6-bisphosphatase (EC 3.1.3.11; FBPase) in potato tubers, we used anti PFP antibodies to ensure that
the assay was specific for FBPase and that PPi:fructose 6-phosphate 1-phosphotransferase (EC 2.7.1.90: PFP) did not contribute
to the production of fructose 6-phosphate (Fru-6-P). The involvement of cytosolic FBPase in cold sweetening was determined
by monitoring enzyme activity during storage ofSolanum tuberosum cv. Erntestolz tubers at 2 or 8°C. In contrast to the rapid increase in sucrose and reducing sugars, the specific activity
of FBPase showed no change and PFP rose slightly during storage at 2°C. Sugar concentrations and enzyme activities remained
virtually unchanged during storage at 8°C. These data allow the interconversion of fructose 1.6-bisphosphate (Fru-1,6-P2) to Fru-6-P and vice versa by FBPase and PFP, respectively, in potato tubers, but do not support a causal relationship between
coarse metabolic control of FBPase and cold-induced sweetening. 相似文献
74.
Kobra Maghsoudi Yahya Emam Muhammad Ashraf Mohammad Javad Arvin 《Journal of plant nutrition》2013,36(17):2121-2132
Role of exogenously-applied silicon (Si) on antioxidant enzyme activities was investigated in wheat under drought stress using a completely randomized factorial design with four replications. Drought stress significantly enhanced activities of ascorbate peroxidase, peroxidase, superoxide dismutase and catalase, and elevated accumulation of osmotically active molecules, soluble sugars and proline. Si application further enhanced activities of enzymes involved in oxidative defense system and accumulation of osmotically active molecules in drought-stressed plants. Under drought stress conditions, water shortage decreased protein content in all cultivars; however, application of Si increased it. Pollen area ratio was lower than 1 for cvs. Shiraz and Marvdasht under drought, but greater than 1 for cvs. Chamran and Sirvan. Water-limited regimes resulted in decreased leaf Ψw in all cultivars, but Si supply was effective in improving Ψw under water-limited regimes. Water shortage increased leaf K, Mg, and Ca concentrations. Under drought stress, Si-treated plants had higher K concentration than the none-treated plants. 相似文献
75.
Kavita Sharma Leonid Asnin Eun Young Ko Eul Tai Lee 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2013,63(2):150-160
Onion cultivar “Sunpower” has growing popularity in Korea due to high storability. The present study considers changes in flavonols, sugars, and two amino acids in onion bulbs during a long-term storage in the ambient dark storage room and in glasshouse equipped with a climate control system. Flavonol and sugar contents were found to fluctuate noticeably during the storage period. Amino acid content remained relatively unchanged till the onset of inner sprouting, increasing afterward. Visible sprouts appeared at week 22 in the dark storage room and for four weeks later in the glasshouse. The bulbs lost 20–30% of their weight depending on storage conditions at the end of the storage trials. At the same time, the content of nutraceutics in study expressed on the dry weight basis remained of the same order of magnitude. The nature of observed variations in chemical composition of onions as well as relation of this phenomenon to physiological development of stored onion bulbs is discussed. A conclusion is made that the “Sunpower” onion cannot sustain overwinter storage. 相似文献
76.
Gediminas Staugaitis Pranas Viškelis 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2013,63(2):176-181
Abstract The study investigates the effects of nitrogen fertilizers on the characteristics of the autumn crop of Chinese cabbage. The rates applied varied from 0 to 225 kg ha?1 (N0, N45, N90, N135, N180, N225); the supply of phosphorus and potassium fertilizers was similar in the all trials, 90 and 150 kg ha?1, respectively. It was found that the optimum nitrogen fertilization rate for the autumn crop of Chinese cabbage was N135. In the case of lower nitrogen rates the yield decreased and the cabbage heads were smaller. Further increase in fertilizer rate (>N135) resulted in a higher percentage of non-standard cabbage heads, while the yield remained almost unchanged compared with N135. The total plant mass of cabbage crop fertilized with N135 was 76 t ha?1; plant residues constituted 33 t ha?1 (43% of the total mass). The yield of market quality cabbage heads was 30 t ha?1 (70% of all the heads produced); the rest of heads were loose, not formed or rot-infected. The optimal amount of total mineral nitrogen (the sum of nitrogen present in the 0–60 cm soil layer and the nitrogen supplied with fertilizers) before planting was 260 kg ha?1. When nitrogen rates were higher than N180 the quality of cabbage heads in terms of the content of vitamin C, nitrates, soluble solids, total solids and sugars decreased. 相似文献
77.
Michael Zech Mario Tuthorn Bruno Glaser Wulf Amelung Bernd Huwe Wolfgang Zech Ludwig Zöller Jörg Löffler 《植物养料与土壤学杂志》2013,176(1):12-15
Precipitation and topsoil samples from a climate transect over the Scandinavian Mountains, Norway, were analyzed for bulk and compound‐specific δ18O values. The natural abundance of 18O in the plant‐derived hemicellulose biomarkers arabinose and xylose correlates positively with δ18O of bulk soil, but not with δ18O of precipitation. This suggests that other factors than δ18Oprec, such as evaporative 18O enrichment of leaf water, exert a strong influence on the natural abundance of 18O in soils. 相似文献
78.
Summary Pot and field experiments were carried out to test fertilizer treatments on the behaviour of potato tubers stores at 4°C and
≥90% relative humidity for 6 months. Weight losses (separated into water and dry matter) were enhanced after N and K fertilization
and decreased by increasing P supply. Glucose and fructose contents were reduced at harvest by high N-fertilizer rates compared
to no or low fertilization, but throughout storage reducing sugar accumulation was increased, sucrose reduction was decreased
and ascorbic acid was increased. K fertilization affected the chemical composition of the tubers somewhat similar to that
of nitrogen fertilization. High initial nitrate content of the tubers seemed to be increased and low nitrate values were decreased
during storage. The tubers from pot experiments showed similar changes but of greater magnitude. 相似文献
79.
Summary Tubers of twelve cultivars ofSolanum tuberosum L., with a varying content of reducing sugars (0.49–2.30 g/100 g fresh weight), were sliced and fermented for up to 48 h
by lactic acid bacteria in a brine of 1.5% NaCl, prior to frying. The content of reducing sugars decreased by 80 to 100%,
depending on the initial sugar level. Colour of chips was measured using the CIE (1976) L*a*b* colour system, where L* is lightness, a* is redness and b* is yellowness of the material and by IBVL colour cards, photographs used for grading the colour of potato chips. L*-values were the best measurement of chip colour. The scale of the IBVL colour cards was too narrow (scale 1–9) for this study,
as chips from eight of the cultivars were scored lighter than IBVL 9 after 48 h of fermentation.
Lighter coloured chips significantly correlated with lower contents of reducing sugars. The sugar content decreased as fermentation
time increased. Fermentation time can thus be used to control potato chip colour, and all the cultivars tested can be used
for production of chips with regard to colour. 相似文献
80.
Summary Reducing sugar and sucrose contents of potato tubers (Solanum tuberosum L.) from six cultivars were monitored both during the growing season and after a four months storage period at 10°C. Significant
correlations were found between tuber sugar contents (sucrose, reducing and total) measured at harvest and the reducing sugar
content after storage. Similarly, in five of the six cultivars, the sucrose loss and the corresponding reducing sugar gain
during storage were significantly correlated. 相似文献