scholarly journals Selection of full-sib families of Panicum maximum Jacq under low light conditions

Revista CERES ◽  
2015 ◽  
Vol 62 (2) ◽  
pp. 199-207
Author(s):  
Douglas Mochi Victor ◽  
Liana Jank ◽  
Beatriz Lempp ◽  
Rosangela Maria Simeão ◽  
Marcos Deon Vilela de Resende ◽  
...  
Keyword(s):  
Shade Tolerance ◽  
Genetic Difference ◽  
Dry Mass ◽  
Panicum Maximum ◽  
Light Conditions ◽  
Low Light ◽  
Breeding Programs ◽  
Light Reduction ◽  
Light Intensities ◽  
Mass Accumulation

The silvopastoral system is a viable technological alternative to extensive cattle grazing, however, for it to be successful, forage grass genotypes adapted to reduced light need to be identified. The objective of this study was to select progenies of Panicum maximum tolerant to low light conditions for use in breeding programs and to study the genetic control and performance of some traits associated with shade tolerance. Six full-sib progenies were evaluated in full sun, 50% and 70% of light reduction in pots and subjected to cuttings. Progeny genotypic values (GV) increased with light reduction in relation to plant height (H) and specific leaf area (SLA). The traits total dry mass accumulation (DM) and leaf dry mass accumulation (LDM) had GV higher in 50% shade and intermediate in 70% shade. The GV of tiller number (TIL) and root dry mass accumulation (RDM) decreased with light reduction. The highest positive correlations were obtained for the traits H and RDM with SLA and DM; the highest negative correlations were between TIL and SLA and RDM, and H and LDM. The progenies showed higher tolerance to 50% light reduction and, among them, two stood out and will be used in breeding programs. It was also found that it is not necessary to evaluate some traits under all light conditions. All traits had high broad sense heritability and high genotypic correlation between progenies in all light intensities. There is genetic difference among the progenies regarding the response to different light intensities, which will allow selection for shade tolerance

scholarly journals Hybrid tea-roses under controlled light conditions. 2. Flowering of seedlings as dependent on the level of irradiance.

1978 ◽  
Vol 26 (1) ◽  
pp. 128-132
Author(s):  
D.P. de Vries ◽  
L. Smeets
Keyword(s):  
Selection Procedure ◽  
Light Conditions ◽  
Low Light ◽  
Light Requirement ◽  
Experimental Conditions ◽  
Light Intensities

Under the experimental conditions described in the preceding abstract, mortality increased with decreasing light intensities. The percentage of flowering seedlings increased and that of aborting ones decreased with irradiance. For the populations studied, no genotype-environment interactions for the percentages of flowering seedlings occurred. A selection procedure for roses with a low light requirement for flowering is considered. (Abstract retrieved from CAB Abstracts by CABI’s permission)

Interactions entre mitochondries et chloroplastes dans la cellule. II. Action du DBMIB, de l'antimycine A et du FCCP sur la spore de Funaria hygrometrica

1977 ◽  
Vol 55 (12) ◽  
pp. 1650-1659 ◽  
Author(s):  
D. Chevallier ◽  
R. Douce ◽  
F. Nurit
Keyword(s):  
Cytochrome Oxidase ◽  
Dark Respiration ◽  
High Light ◽  
Light Conditions ◽  
Oxygen Production ◽  
Low Light ◽  
Funaria Hygrometrica ◽  
Light Intensities

The effect of DBMIB, antimycine A, and FCCP on respiration and photosynthesis of intact chlorophyllic moss (Funaria hygrometrica) spore was investigated.Antimycine A (1 μM) strongly inhibited dark respiration, was without effect on photosynthesis at high light intensities (above the saturation plateau values), and stimulated photosynthesis at low light intensities (below the saturation plateau values).DBMIB (3 μM) inhibited photosynthesis and was without effect, even under light conditions, on the dark respiration. Low amount of FCCP (3 μM) partially inhibited oxygen production at high light intensities. In this case, the inhibition observed was partially relieved by 1 μM antimycine A or 30 μM of KCN; higher concentration of FCCP totally inhibited the oxygen production.It seems likely, therefore, that in the chlorophyllic moss spore the cytochrome oxidase pathway is not functioning under high light intensities and that this inhibition of respiration is attributable to the low cytoplasmic ADP:ATP ratio.

scholarly journals Low Light Availability Reduces the Subsurface Sediment Carbon Content in Halophila beccarii From the South China Sea

2021 ◽  
Vol 12 ◽  
Author(s):  
Chanaka Premarathne ◽  
Zhijian Jiang ◽  
Jialu He ◽  
Yang Fang ◽  
Qiming Chen ◽  
...  
Keyword(s):  
Carbon Content ◽  
Light Availability ◽  
Seagrass Beds ◽  
Biomass Carbon ◽  
Light Conditions ◽  
Above Ground Biomass ◽  
Low Light ◽  
Subsurface Sediment ◽  
Light Intensities ◽  
Sediment Carbon

Eutrophication, dredging, agricultural and urban runoffs, and epiphyte overgrowth could reduce light availability for seagrass. This may affect “blue carbon” stocks in seagrass beds. However, little research is available on the effect of light intensities on carbon sequestration capacity in seagrass beds, especially small-bodied seagrasses. The dominant seagrass Halophila beccarii, a vulnerable species on the IUCN Red List, was cultured in different light intensities to examine the response of vegetation and sediment carbon in seagrass beds. The results showed that low light significantly reduced leaf length and above-ground biomass, while carbon content in both above-ground and below-ground tissues were not affected. Low light reduced both the above-ground biomass carbon and the total biomass carbon. Interestingly, while under saturating light conditions, the subsurface and surface carbon content was similar, under low light conditions, subsurface sediment carbon was significantly lower than the surface content. The reduction of subsurface sediment carbon might be caused by less release flux of dissolved organic carbon from roots in low light. Taken together, these results indicate that reduced light intensities, to which these meadows are exposed to, will reduce carbon sequestration capacity in seagrass beds. Measures should be taken to eliminate the input of nutrients on seagrass meadows and dredging activities to maintain the “blue carbon” storage service by enhancing light penetration into seagrass.

Responses to shading of seedlings of savanna grasses (with different C4 photosynthetic pathways) in Botswana

1993 ◽  
Vol 9 (2) ◽  
pp. 213-229 ◽  
Author(s):  
E. M. Veenendaal ◽  
D. D. Shushu ◽  
J. M. O. Scurlock
Keyword(s):  
Moisture Stress ◽  
Tree Canopy ◽  
Grass Species ◽  
Response Analysis ◽  
Panicum Maximum ◽  
Light Saturation ◽  
Low Light ◽  
Relative Growth ◽  
Light Intensities ◽  
Digitaria Eriantha

ABSTRACTDifferent C4 photosynthesis pathways may influence plant response to shade and/or moisture stress. In the savanna of south-eastern Botswana, seedlings of PCK C4 type grass species were frequently observed to emerge in shaded habitats. The speciesDigitaria erianthasubsp.pentzii, which shows the NADP-ME pathway, was also found to be associated with the tree canopy. Species emerging in habitats exposed to full sun often showed the NAD-ME C4 pathway. Seedlings orAristida congesla, Eragrostis rigidiorandTragus berteronianuswhich normally emerge in full light, showed higher relative growth rates and/or unit leaf rates compared with seedlings ofPanicum maximumandUrochloa panicoideswhich are associated with shaded habitats. Seedlings of the latter species, however, survived low light conditions. Relative growth rate of the seedlings appeared to be negatively related to caryopsis weight. Light response analysis of leaves ofDigitaria erianthasubsp.pentzii, grown under low light intensities, showed similar trends in light saturation to those reported for the PCK type inPanicum maximum. Mesophyll rather than stomatal limitations appeared to induce light saturation at higher light intensities in leaves grown under shade conditions.

Optimal NH 4 + /NO 3 ‐ ratios enhanced the shade tolerance of soybean seedlings under low light conditions

Plant Biology ◽  
2020 ◽  
Author(s):  
Ali Raza ◽  
Muhammad Ahsan Asghar ◽  
Sajad Hussain ◽  
Cheng Bin ◽  
Iram Shafiq ◽  
...  
Keyword(s):  
Shade Tolerance ◽  
Light Conditions ◽  
Low Light ◽  
Soybean Seedlings

Cold tolerance and winter hardiness in Lolium perenne: II. Influence of light and temperature during growth and hardening

1973 ◽  
Vol 80 (2) ◽  
pp. 341-348 ◽  
Author(s):  
T. Lawrence ◽  
J. P. Cooper ◽  
E. L. Breese
Keyword(s):  
Light Intensity ◽  
Cold Tolerance ◽  
Lolium Perenne ◽  
Water Soluble ◽  
Light Conditions ◽  
Low Light ◽  
Growing Period ◽  
Light Intensities ◽  
Lower Light ◽  
Light Input

SummaryIn the first paper of this series it was shown that Lolium perenne material required hardening periods involving low, but above freezing, temperatures before frost tolerance was achieved. The present experiments show that the light conditions during the hardening and prehardening periods are also important. At both stages a reduction in total light energy reduced subsequent cold tolerance but the relative effects of light intensity and photoperiod differed between the prehardening and hardening treatments. Thus low light input during the hardening period at 2 CC reduced cold tolerance most when given at higher intensities over shorter days (8 h) while during the prehardening growing period at 20 °C the reduction was greatest when the lower light input was given at low intensity over longer days (16 h).Varieties of different climatic origins reacted differentially to the treatments. The Mediterranean variety Fano was particularly adversely affected by low light intensities during hardening and also benefited from higher temperatures during the prehardening growing period. With higher light intensities and higher growth temperatures this Mediterranean variety approached the more northern material in cold tolerance; but as a corollary it was clear that the N. European variety Veja was able to harden under lower light conditions, and lower growing temperatures. The varieties Melle and S. 321 from intermediate latitudes, were intermediate in response.Although water soluble carbohydrate content was increased during the hardening period, except at the lowest light intensity (2·9 W/m2), no simple relationship between the WSC content and the cold tolerance of the different varieties could be detected.The results provide a useful guide to the pre-treatments necessary to discriminate between varieties for cold tolerance in such a way that the results can be correlated with field performance.

Growth responses of three contrasting Piper species growing under different light conditions

1990 ◽  
Vol 68 (6) ◽  
pp. 1182-1186 ◽  
Author(s):  
M. Esther Sanchez-Coronado ◽  
Emmanuel Rincòn ◽  
Carlos Vàzquez-Yanes
Keyword(s):  
Growth Chamber ◽  
Los Tuxtlas ◽  
Light Conditions ◽  
Growth Responses ◽  
Low Light ◽  
Light Intensities ◽  
Shade Tolerant Species ◽  
Piper Auritum ◽  
Plastic Responses ◽  
Tropical Station

The growth responses of Piper aequale, Piper auritum, and Piper hispidum under contrasting light conditions at Los Tuxtlas Tropical Station, Mexico, and in growth chamber experiments were investigated. The species showed contrasting growth responses; Piper auritum was the less shade-tolerant species and Piper aequale, on the contrary, showed the ability to exploit conditions of intermediate light intensities, similar to those found in small gaps. Piper hispidum was able to sustain growth in both high and low light conditions; this response appears to be related with morphological plastic responses.

scholarly journals Hybrid tea-roses under controlled light conditions. 3. Flower and blind shoot production in the glasshouse of seedlings selected for flowering or flower bud abortion at low irradiances in a growth room.

1978 ◽  
Vol 26 (4) ◽  
pp. 399-404
Author(s):  
D.P. de Vries ◽  
L.A.M. Dubois ◽  
L. Smeets
Keyword(s):  
Lower Percentage ◽  
Light Conditions ◽  
Flower Bud ◽  
Low Light ◽  
Light Intensities ◽  
Shoot Production ◽  
Growth Room ◽  
Selection For ◽  
Flower Bud Abortion ◽  
Made In

Seedlings of hybrid tea roses, previously selected in a growth room for flowering or flower bud abortion at low light intensities were grown in a greenhouse for periods of at least 14 months. Previously flowering seedlings whether grown on their own roots or on a rootstock yielded more flowers, particularly in winter, than previously aborting ones. This was due to a lower percentage of blind shoots and a tendency to produce more shoots. It was shown that selection for better winter performance under glass could be made in young seedlings. [For part 2 see HcA 48, 7528.] (Abstract retrieved from CAB Abstracts by CABI’s permission)

scholarly journals Growth and Yield of Okra (Abelmoschus esculentus Moench) as Influenced by Compost Application under Different Light Intensities

2015 ◽  
Vol 7 (2) ◽  
pp. 217-226 ◽  
Author(s):  
Victor A. DADA ◽  
Sifau A. ADEJUMO
Keyword(s):  
Light Intensity ◽  
Leaf Area ◽  
Abelmoschus Esculentus ◽  
Growth And Yield ◽  
Dry Matter Accumulation ◽  
Low Light ◽  
Light Reduction ◽  
Low Light Intensity ◽  
Light Intensities ◽  
Leaf Formation

Okra (Abelmoschus esculentus) is one of the popular vegetables, especially rich in iron, vitamins and other minerals. Poor soil fertility and inconsistent light intensity, due to unfavorable weather condition, reduce okra performance. Response of two okra varieties (‘NH47-4’ and ‘Clemson spine’) to different rates of compost (0, 5, 10 and 15 t/ha), under different light intensities (L0: control (no reduction) or 100% light intensity, L1: 33%, L2: 46% and L3: 76%, light reduction) were assessed in pot and field trials. The experimental design was a factorial experiment fitted in a randomized complete block design (RCBD). Data on growth and yield attributes were collected. The results showed that the reduction in light intensity (L3) increased the numbers of fruits and leaf area by 50 and 47% respectively on the field, but delayed flowering. High light intensity (L0) though enhanced leaf area formation and early flowering, but hastened leaf senescence and abscission. Compost generally increased growth rate, leaf area and dry matter accumulation of the two okra cultivars compared to control under varying light intensities. Compost at 15 t/ha performed better and increased fruit number by 66% on the field. Between the two cultivars, ‘Clemson spine’ responded better than ‘NH47-4’ plants in terms of yield. Low light intensity (76% light reduction) in combination with higher compost rate however enhanced prolonged fruiting and leaf formation in the two okra varieties. The application of compost at 15 t/ha is therefore recommended for optimum yield of okra under low light intensity.

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