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71.
Effects of Growth Regulators on Polyamine Content and Peroxidase Activity in Hevea brasiliensis Callus 总被引:2,自引:0,他引:2
3, 4-dichlorophenoxyacetic acid (3,4-D) and benzylaminopurine(BAP) at 9 µM (control medium) was compared with 4.5,2.25, and 0.45 µM for ability to induce callogenesis andembryogenesis from seed explants of Hevea brasiliensis. Supplyingthese growth regulators at 4.5 µM for 20 d improved embryogenicpotential compared with the control medium (El Hadrami, Carronand d'Auzac, 1991, Annals of Botany 67, 511515), sustainedputrescine, spermidine and spermine at a higher level throughoutof much of the culture period (4070 d), and maintainedlow levels of peroxidase activity. In the control medium, poorcallus embryogenesis is considered a consequence of rapid ageingof tissues characterized by (i) acceleration of an early buttransient production of polyamines, which promoted embryogeniccapacity, and (ii) an early peak in peroxidase activity thatwas positively correlated with callus browning, one of the factorslimiting embryogenesis. Somatic embryogenesis, polyamines, peroxidase, Hevea brasiliensis, rubber-tree 相似文献
72.
The increase of glucose-6-phosphate dehydrogenase (G-6-PD) activityhas been proposed as an early marker of floral evocation inthe shoot apical meristem of spinach. This induction is obtainedby the transfer of vegetative plants from short days to continuouslight. The exposure of a single leaf to continuous light inducedthe same effect as that produced with the whole plant. In vegetativeconditions (short days), an electrical potential of ten volts(electrical current: 12·5 µA) applied to the petioleof a single leaf induced a weak increase of G-6-PD activityin the shoot apex, while under inductive conditions, this increasewas similar to that of control plants (transferred to continuouslight). Application of an electrical potential to the petioleand the root inhibits the increase linked to the inductive transfer.These results show that an externally applied electrical potentialmay interact with the natural electrical gradients along theshoot and consequently inhibit the normal floral developmentby an as yet unspecified mechanism. Spinacia oleracea, floral induction, interorganic relations, glucose-6-phosphate dehydrogenase, shoot apex, electrical potentials 相似文献
73.
A statistical method for analyzing sensory profiling data obtained by means of fixed vocabulary or free choice profiling is discussed. The most interesting feature of this method is that it involves only simple statistical treatment and can therefore be performed using standard software packages. The outcomes of this method are compared to those of Generalized Procrustes Analysis on the basis of two data sets obtained, respectively, by means of fixed vocabulary and free choice profiling. A significance test is also discussed in order to assess whether the overall configuration of the products is meaningful. This significance test is based upon a simulation study involving the permutation procedure. 相似文献
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The vegetative growth of Dactylis glomerata L. in sand was studiedunder controlled light, temperature, and nutritional conditions.Plants were daily supplied with three nutrient solutions ofdifferent nitrate concentrations (102, 103 and2 x 104 mol I1). For each concentration, growthobeyed an exponential law between the fourth and seventh weeksafter sowing. The time constant of the exponential was the samefor the shoot as for the root, and showed no significant variationwith nitrate concentration. The kinetic results and the strong dependence of the root: shootratio on nitrate concentration are discussed on the basis ofThornley's model. Hypothesizing that the molecular mechanismsof nitrate absorption are independent of the nitrate concentrationof the nutrient solution, we derived a relationship betweenthe root: shoot ratio and nitrate concentration. This relationshipwas found to be compatible with the experimental results. Dactylis glomerata L., vegetative phase, kinetics of growth, root: shoot equilibrium, nitrate absorption 相似文献
76.
JELTE ROZEMA STEF WEIJERS ROB BROEKMAN PETER BLOKKER BERT BUIZER CHANTAL WERLEMAN HASSAN EL YAQINE HANNEKE HOOGEDOORN MIGUEL MAYORAL FUERTES ELISABETH COOPER† 《Global Change Biology》2009,15(7):1703-1715
Annual growth of the polar evergreen shrub Cassiope tetragona on Svalbard was evaluated as a proxy for Arctic summer temperatures. Transfer functions were derived from temperature‐growth correlations of shoots and from a temperature‐growth response, obtained from experimental warming using open top chambers (OTC) in high Arctic tundra vegetation at Isdammen approximately 1.5 km southeast of Longyearbyen, Svalbard (78°N, 15 E) and in Longyeardalen, 3 km west of Isdammen from 2004 to 2006. Air temperatures, monitored throughout the summer months, were 1.3 °C higher inside the OTCs than in the control plots. Annual stem growth was measured by tagging stems and leaves, and in the lab with shoots harvested from OTCs and control plots. Annual growth parameters assessed were leaf production, sum of length and weight of individual leaves, and stem length increment derived from leaf scar distances and the distances between wintermarksepta in the stem. Wintermarksepta are formed at the end of the summer growth period when the pith is narrowing and consist of dense and dark tissue ( Fig. 1b ). The variation of annual growth in a 34‐year site chronology (based on Cassiope shoots from the surroundings of the OTCs and control plots) correlated strongly with the mean summer temperature on Svalbard. The number of leaf pairs, leaf length and stem length also increased in the OTC warmed plots in the second and third year of warming. Transfer functions were derived from the temperature‐annual growth correlations from a single shoot from Longyeardalen, from the cross‐dated Isdammen site chronology and from the growth response to experimental warming. Based on leaf scar distances and distances between wintermarksepta of well‐preserved subfossil shoots in arctic tundra soil, annual stem length increase was assessed for the layers of a soil core collected at the Isdammen site. Based on the derived transfer functions summer temperature of the period relating to the 15 cm deep tundra soil core layer, radiocarbon dated at 4230±40 bp , may have been 3.0 °C lower than the present‐day 6.2 °C value. These results indicate that the transfer functions can be used to reconstruct past temperatures, beyond the time range of instrumental temperature and ice core records of Svalbard.
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79.
Alhan Sariyev Celaleddin Barutcular Mert Acar Akbar Hossain Ayman EL Sabagh 《Phyton》2020,89(3):519-528
Maize being sub-tropical crop is sensitive to water deficit during the
early growth stages; particularly clay-rich soil, due to the compaction of the soil.
It is well-documented that potential sub-surface drip irrigation (SDI) (Full irrigation; SDIFull (100% field capacity (FC)), Deficit irrigation; SDIDeficit (70% FC))
improves water use efficiency, which leads to increased crop productivity; since it
has a constraint that SDI excludes soil air around the root-zone during irrigation
events, which alter the root function and crop performance. Additionally, in clayrich soils, the root system of plants generally suffers the limitation of oxygen,
particularly the temporal hypoxia, and occasionally from root anoxia; while
SDI system accomplishes with the aerating stream of irrigation in the rhizosphere
could provide oxygen root environment. The oxygen can be introduced into the
irrigation stream of SDI through two ways: the venturi principle, or by using solutions of hydrogen peroxide through the air injection system. Therefore, the application of hydrogen peroxide (H2O2; HP) can mitigate the adverse effect of soil
compactness and also lead to improving the growth, yield and yield attributes
of maize in clay-rich soil. Considering the burning issue, a field study was conducted in consecutive two seasons of 2017 and 2018; where hybrid maize was
cultivated as a second crop, to evaluate the effect of liquid-injection of H2O2
(HP) into the irrigation stream of SDI on the performance of maize in a clay-rich
soil field of Adana, Turkey. When soil water content decreased in 50% of available water, irrigation was performed. The amount of water applied to reach the
soil water content to the field capacity is SDIFull (100% FC) and 70% FC of this
water is SDIDeficit (70% FC). In the irrigation program, hydrogen peroxide (HP)
was applied at intervals of 7 days on average according to available water with
and without HP: SDIFull (100% FC) + 0 ppm HP with full SDI irrigation;
SDIFull (100% FC) + 250 ppm HP with deficit SDI irrigation; SDIDeficit
(70% FC) + 0 ppm HP, SDIDeficit (70% FC) + 250 ppm HP and SDIDeficit
(70% FC) + 500 ppm HP. Deficit irrigation (SDIDeficit (70% FC)) program
was started from tasseling stage and continued up to the physiological maturity
stage with sub-soil drip irrigation. H2O2 was applied 3 times during the growing season. Two years’ results revealed that the liquid-injection of H2O2 into the irrigation stream of SDI improved the growth and yield-related attributes and grain
yield of maize. Based on the obtained results, during the extreme climatic condition in the year 2017, SDIFull (100% FC) + 250 ppm HP was more effective than
SDIFull (100% FC) + 0 ppm HP on all traits for relative to full irrigation. While,
during the favourable climatic condition in the 2018 season, SDIFull (100% FC)
+ 250 ppm HP was more effective than full irrigation with SDIFull (100% FC) +
0 ppm HP for the grain yield, grains, and SPAD value. Accordingly, the most
effective treatment was SDIFull (100% FC) + 250 ppm HP, as it gave the highest
growth and yield-related attributes and grain yield of maize followed by
SDIDeficit (70% FC) + 250 ppm HP. Therefore, SDIFull with 250 ppm H2O2
using as liquid-injection may be recommended to mitigate the adverse effect of
soil compactness particularly water-deficit stress in clay-rich soil for the sustainability of maize production. 相似文献
80.
Zahoor Ahmad Ejaz Ahmad Waraich Celaleddin Barutçular Akbar Hossain Murat Erman Fatih ÇIĞ Hany Gharib Ayman EL Sabagh 《Phyton》2020,89(3):529-539
The main objective of the research is to assess the role of foliar application of silicon (Si) for enhancing the survival ability of wheat under drought stress
through improving its morphology, physicochemical and antioxidants activities.
Treatments were five doses of Si at the rate of 2, 4, 6 and 8 mM and a control. After
completion of seeds germination, pots were divided into four distinct groups at various field capacity (FC) levels, such as 100% FC (well-irrigated condition), 75% FC
(slight water deficit), 50% FC (modest water deficit) and 25% FC (severe water deficit stress condition). Foliar application of Si at the rate of 2, 4, 6 and 8 mM and a
control were given after 30 days of sowing at the tillering stage of wheat. Findings
of the present investigation indicated that increasing the level of water deficit stress
reduced the morphological parameters (such as root and shoot fresh and dry-biomass weight) and physico-biochemical events ((such as chlorophyll contents by
estimating SPAD value), total free amino acid (TFAA), total soluble sugar (TSS),
total soluble protein (TSP), total proline (TP), CAT (catalase), POD (peroxidase),
SOD (superoxide dismutase) and APX (ascorbate peroxidase)) of wheat; while
foliar application of Si at 6 mM at tillering stage enhanced the drought tolerance
in wheat by increasing morphology and physiochemical characters under all levels
of drought stress. Similarly, antioxidants activities in wheat also enhanced by the
application of Si at 6 mM under normal as well as all drought stress levels. Therefore, it may be concluded that foliar application of Si at 6 mM at the tillering stage
of wheat is an important indication for increasing the drought tolerance by improving the morphology, physico-biochemical and antioxidants activities in plants under
deficit water (drought) conditions. 相似文献