Effects of drought during grain filling on PS II activity in rice

2005 ◽  
Vol 162 (8) ◽  
pp. 903-911 ◽  
Author(s):  
Alejandro J. Pieters ◽  
Susana El Souki
Keyword(s):  
Grain Filling ◽  
Ps Ii ◽  
Effects Of Drought ◽  
Ps Ii Activity

Isolierung von PS II-Partikeln mit in vivo Eigenschaften aus Euglena gracilis, Stamm Z / Isolation of PS II-Particels with in vivo Characteristics from Euglena gracilis, Stamm Z

1982 ◽  
Vol 37 (3-4) ◽  
pp. 256-259 ◽  
Author(s):  
F. Schuler ◽  
P. Brandt ◽  
W. Wießner
Keyword(s):  
Euglena Gracilis ◽  
Fluorescence Emission ◽  
Improved Method ◽  
Ps Ii ◽  
Ps I ◽  
Emission And Absorption Spectra ◽  
Chlorophyll Protein ◽  
Ps Ii Activity ◽  
Photosystem Ii Particles

Abstract An improved method for isolation of (photosystem II)-particles from Euglena gracilis, strain Z was established. PS II-particles isolated by ultrasonic treatment and following differential centrifugation show fluorescence emission and absorption spectra identical with in vivo properties of Euglena gracilis. These PS II-particles have only PS II-activity and contain CP a, the typical chlorophyll-protein-complex of PS II. No contamination of PS I-components are detectable.

A drought experiment using mobile shelters: the effect of drought on barley yield, water use and nutrient uptake

1978 ◽  
Vol 91 (3) ◽  
pp. 599-623 ◽  
Author(s):  
W. Day ◽  
B. J. Legg ◽  
B. K. French ◽  
A. E. Johnston ◽  
D. W. Lawlor ◽  
...  
Keyword(s):  
Grain Yield ◽  
Nutrient Uptake ◽  
Soil Water ◽  
Water Deficit ◽  
Water Use ◽  
Grain Filling ◽  
Maximum Depth ◽  
Soil Water Deficit ◽  
Drought Treatment ◽  
Effects Of Drought

SummaryAutomatic mobile shelters were used to keep rain off a barley crop in a drought experiment. The treatments ranged from no water during the growing season to regular weekly irrigation. This paper reports the effect of drought on the harvest yield and its components, on water use and nutrient uptake.Drought caused large decreases in yield, and affected each component of the grain yield. The magnitude of each component varied by up to 25% between treatments, and much of the variation could be accounted for by linear regression against the mean soil water deficit in one of three periods. For the number of grains per ear, the relevant period included tillering and ear formation; for the number of ears per unit ground area, the period included stem extension and tiller death; for grain mass, the period included grain filling.The harvest yields were linearly related to water use, with no indication of a critical period of drought sensitivity. The relation of grain yield to the maximum potential soil water deficit did show that a prolonged early drought had an exceptionally large effect on both yield and water use.Two unsheltered irrigation experiments, also on barley, were made in the same year on a nearby site. The effects of drought on yield in these experiments were in good agreement with the effects observed on the mobile shelter site.When fully irrigated, the small plots under the mobile shelters used water 11% faster than larger areas of crop, because of advection. The maximum depth from which water was extracted was unaffected by the drought treatment. When 50% of the available soil water had been used the uptake rate decreased, but the maximum depth of uptake continued to increase.Measurements of crop nutrients at harvest showed that nitrogen uptake was large, because of site history, and that phosphate uptake was decreased by drought to such an extent that phosphate shortage may have limited yield.

The ability of wheat cultivars to withstand drought in UK conditions: formation of grain yield

2002 ◽  
Vol 138 (2) ◽  
pp. 153-169 ◽  
Author(s):  
M. J. FOULKES ◽  
R. K. SCOTT ◽  
R. SYLVESTER-BRADLEY
Keyword(s):  
Grain Yield ◽  
Drought Resistance ◽  
Water Availability ◽  
Dry Matter ◽  
Grain Filling ◽  
Temperate Climate ◽  
Soluble Carbohydrate ◽  
Wheat Cultivars ◽  
Effects Of Drought ◽  
Yield Responses

Experiments in three dry years, 1993/94, 1994/95 and 1995/96, on a medium sand at ADAS Gleadthorpe, England, tested responses of six winter wheat cultivars to irrigation of dry-matter growth, partitioning of dry matter to leaf, stem and ear throughout the season, and to grain at final harvest. Cultivars (Haven, Maris Huntsman, Mercia, Rialto, Riband and Soissons) were selected for contrasts in flowering date and stem soluble carbohydrate. Maximum soil moisture deficit (SMD) exceeded 140 mm in all years, with large deficits (>75 mm) from early June in 1994 and from May in 1995 and 1996. The main effects of drought on partitioning of biomass were for a decrease in the proportion of the crop as lamina in the pre-flowering period, and then earlier retranslocation of stem reserves to grains during the first half of grain filling. Restricted water availability decreased grain yield by 1·83 t/ha in 1994 (P<0·05), and with more prolonged droughts, by 3·06 t/ha in 1995 (P<0·001) and by 4·55 t/ha in 1996 (P<0·001). Averaged over the three years, grain yield responses of the six cultivars differed significantly (P<0·05). Rialto and Mercia lost only 2·8 t/ha compared with Riband and Haven which lost 3·5 t/ha. Losses for Soissons and Maris Huntsman were intermediate. In the two years with prolonged drought, the biomass depression was on average greater for Haven (6·0 t/ha) than for Maris Huntsman (4·2 t/ha) (P<0·05). Thus, the grain yield sensitivity of Haven to drought derived, in part, from a sensitivity of biomass growth to drought. Harvest index (HI; ratio of grain to above-ground dry matter at harvest) responses of the six cultivars to irrigation also differed (P<0·05) and contributed to the yield responses. The smallest decrease in HI of the six cultivars with restricted water availability was shown by Rialto (−0·033); this partially explained the drought resistance for this cultivar. The largest decrease was for Maris Huntsman (−0·072). The cultivars differed in flowering dates by up to 9 days but these were poorly correlated with grain yield responses to irrigation. Stem soluble carbohydrate at flowering varied amongst cultivars from 220 to 300 g/m2 in the unirrigated crop; greater accumulation appeared to be associated with better maintenance of HI under drought. It is concluded that high stem-soluble carbohydrate reserves could be used to improve drought resistance in the UK's temperate climate, but that early flowering seems less likely to be useful.

scholarly journals Reversible particle movements associated with unstacking and restacking of chloroplast membranes in vitro.

1976 ◽  
Vol 71 (1) ◽  
pp. 136-158 ◽  
Author(s):  
L A Staehelin
Keyword(s):  
Plasma Membranes ◽  
Structural Changes ◽  
Freeze Fracture ◽  
Chloroplast Membranes ◽  
Ps Ii ◽  
Membrane Particles ◽  
Intramembranous Particles ◽  
Membrane Surfaces ◽  
Ps Ii Activity

Freeze-fracture and freeze-etch techniques have been employed to study the supramolecular structure of isolated spinach chloroplast membranes and to monitor structural changes associated with in vitro unstacking and restacking of these membranes. High-resolution particle size histograms prepared from the four fracture faces of normal chloroplast membranes reveal the presence of four distinct categories of intramembranous particles that are nonrandomly distributed between grana and stroma membranes. The large surface particles show a one to one relationship with the EF-face particles. Since the distribution of these particles between grana and stroma membranes coincides with the distribution of photosystem II (PS II) activity, it is argued that they could be structural equivalents of PS II complexes. An interpretative model depicting the structural relationship between all categories of particles is presented. Experimental unstacking of chloroplast membranes in low-salt medium for at least 45 min leads to a reorganization of the lamellae and to a concomitant intermixing of the different categories of membrane particles by means of translational movements in the plane of the membrane. In vitro restacking of such experimentally unstacked chloroplast membranes can be achieved by adding 2-20 mM MgCl2 or 100-200 mM NaCl to the membrane suspension. Membranes allowed to restack for at least 1 h at room temperature demonstrate a resegregation of the EF-face particles into the newly formed stacked membrane regions to yield a pattern and a size distribution nearly indistinguishable from the normally stacked controls. Restacking occurs in two steps: a rapid adhesion of adjoining stromal membrane surfaces with little particle movement, and a slower diffusion of additional large intramembranous particles into the stacked regions where they become trapped. Chlorophyll a:chlorophyll b ratios of membrane fraction obtained from normal, unstacked, and restacked membranes show that the particle movements are paralleled by movements of pigment molecules. The directed and reversible movements of membrane particles in isolated chloroplasts are compared with those reported for particles of plasma membranes.

Effects of Drought Stress on Activity of Photosystems in Leaves of Maize at Grain Filling Stage

2009 ◽  
Vol 35 (10) ◽  
pp. 1916-1922 ◽  
Author(s):  
Geng LI ◽  
Hui-Yuan GAO ◽  
Bin ZHAO ◽  
Shu-Ting DONG ◽  
Ji-Wang ZHANG ◽  
...  
Keyword(s):  
Drought Stress ◽  
Grain Filling ◽  
Filling Stage ◽  
Effects Of Drought ◽  
Grain Filling Stage

Interaction of pretilachlor with PS-II activity of the cyanobacterium Desmonostoc muscorum PUPCCC 405.10

2020 ◽  
Vol 60 (6) ◽  
pp. 532-542
Author(s):  
Gurdeep Kaur Swatch ◽  
Davinder Pal Singh ◽  
Jasvirinder Singh Khattar ◽  
Pradipta Kumar Mohapatra
Keyword(s):  
Ps Ii ◽  
Ps Ii Activity

Effect of Irradiation and Immobilization on Spinach Chloroplast Activities

1980 ◽  
Vol 35 (5-6) ◽  
pp. 477-481 ◽  
Author(s):  
T. Fujimura ◽  
F. Yoshii ◽  
I. Kaetsu ◽  
Y. Inoue ◽  
K. Shibata
Keyword(s):  
Low Temperature ◽  
Active Center ◽  
Polymer Matrix ◽  
O2 Evolution ◽  
Hydrophilic Polymer ◽  
Spinach Chloroplast ◽  
Ps Ii ◽  
Thermo Stability ◽  
Ps Ii Activity ◽  
Isolated Chloroplasts

Abstract The effect of y-ray irradiation and immobilization by means of radiation polymerization on PS II activity (O2 evolution) of isolated chloroplasts from spinach was investigated. Reduction of O2 evolution activity by irradiation was small at lower temperatures below – 24 °C, but the activity decreased slightly by freezing at extremely low temperature below –78 °C. So the optimum low temperature range for the treatment was observed. The immobilized chloroplast in a hydrophilic polymer matrix showed the stable duration of O2 evolution activity more than 700 h at 4 °C . Thermo-stability of chloroplast was also improved greatly by immobilization. The active center of PS II in immobilized chloroplasts was retained even after 60 min standing at 50 °C.

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