Responses to light changes in tropical seedlings of the Brazilian Atlantic rainforest tree species Cecropia glazioui (Cecropiaceae) and Cedrela fissilis (Meliaceae)

2007 ◽  
Vol 55 (8) ◽  
pp. 795 ◽  
Author(s):  
Maria Terezinha Silveira Paulilo ◽  
Sonia Regina Duz ◽  
Alexandre Siminski ◽  
Marisa Santos
Keyword(s):  
High Light ◽  
Low Light ◽  
Relative Growth ◽  
Light Regimes ◽  
Light Gradient ◽  
Trait Plasticity ◽  
Mean Relative Growth Rate ◽  
The Mean ◽  
Net Assimilation ◽  
Sun Light

This study analysed the behaviour of Cecropia glazioui Sneth. and Cedrela fissilis Vell. seedlings across a 2–50% full sun light gradient. The morphological adjustments of the seedlings to the different light regimes were interpreted as means of light interception in low light and avoidance of water stress in high light conditions. Cecropia seedlings showed greater trait plasticity at the 2–15% light interval, whereas Cedrela seedlings showed a slight tendency to present greater trait plasticity at the 15–30% light interval than the 2–15% interval. The seedlings of both species did not fully acclimate to decreasing light, showing lower values for the mean relative growth rate (RGR) components, leaf area ratio (LAR) and net assimilation rate (NAR) than seedlings under constant low light, but acclimated to increasing light, showing higher values for RGR components than seedlings under constant high light. The general responses to light gradient in these two species indicate their relative tolerance and ability to grow at low and high light and provide traits used in coping with gap dynamics. The results also indicated that the two species differed in their shade tolerance.

scholarly journals THE EFFECT OF MID-SEASON VINE REMOVAL ON THE GROWTH OF FIVE SWEETPOTATO (IPOMOEA BATATAS L.) CULTIVARS

HortScience ◽  
1993 ◽  
Vol 28 (4) ◽  
pp. 266E-266
Author(s):  
Victor A. Kahn ◽  
C. Stevens ◽  
T. Mafolo ◽  
C. Bonsi ◽  
J.Y. Lu ◽  
...  
Keyword(s):  
Growth Rate ◽  
Leaf Area ◽  
Relative Growth Rate ◽  
Assimilation Rate ◽  
Marketable Yield ◽  
Relative Growth ◽  
Crop Growth Rate ◽  
Mean Relative Growth Rate ◽  
The Mean ◽  
Net Assimilation

TU-82-155 and `Georgia-Jet' early maturing. `Carver II', TU-1892 and `Rojo-Blanco' late maturing sweetpotato, cultivars were evaluated in the field for 0.20 and 40% vine removal (VR) at 8 wk after transplanting. Parameters measured were: leaf area index (LAI) recovery, net assimilation rate, foliage crop growth rate (FCGR), storage roots crop growth rate (RCGR). alpha a (the mean relative growth rate in dry wt to the mean relative growth rate in leaf area over a time interval) or the partitioning of assimilates, total and marketable yield. A split. splitplot design was used and plants were sampled at 3 and 8 wk following VR. Except for TU-82-155 all cultivars showed significant LAI recovery above the control at 3 and 8 wk after vine removal when 20% of the vines were removed while at the 40% VR, only 'Georgia-Jet'. TU-1892 and 'Carver II' showed significant increases in LAI for the same periods. Net assimilation rate showed significant interactions while FCGR was not significantly affected by either 20 or 40 VR compared to the control at 3 or 8 wk after VR. RCGR was significantly affected by both levels of VR at 3 and 8 wk after VR and surplus assimilates (alpha a) showed significant interactions between cultivars and % VR. Told yield declined for all cultivars irrespective to maturity groups with the sharpest decrease being at the 20% VR. All cultivars except TU-82-155 showed a decrease in marketable yield, the increase in marketable yield of TU-82-155 was due to a lower non-marketable yield.

scholarly journals GROWTH ANALYSIS OF FIVE SWEETPOTATO (IPOMOEA BATATAS L) CULTIVARS

HortScience ◽  
1993 ◽  
Vol 28 (4) ◽  
pp. 267E-267
Author(s):  
Victor A Khan ◽  
C. Stevens ◽  
T. Mafolo ◽  
C. Bonsi ◽  
J.Y. Lu ◽  
...  
Keyword(s):  
Growth Rate ◽  
Leaf Area ◽  
Assimilation Rate ◽  
Relative Growth ◽  
Crop Growth Rate ◽  
Early Maturing ◽  
Mean Relative Growth Rate ◽  
The Mean ◽  
Net Assimilation ◽  
Maturity Groups

TU-82-155 and `Georgia-Jet' early maturing. `Carver II'. TU-1892 and `Rojo-Blanco' late maturing sweepotato cultivars were evaluated in the field for: leaf area index (LAI), net assimilation rate, foliage crop growth rate (FCGR), storage roots crop growth rate (RCGR) and alpha a (the mean relative growth rate in dry wt to the mean relative growth rate in leaf area over a time interval) or the partitioning of assimilates. A split plot design was used and plants were sampled at 6, 8, 11 and 16 wk after transplanting. The results from study showed that LAI reached maximum development 8 and 12 wk after transplanting for early and late maturing cultivars, respectively. All cultivars irrespective to maturity groups showed a reduction in net assimilation rate 6 wk after transplanting while FCGR for early maturing cultivars gradually declined 6 wk after transplanting and varied among late maturing cultivars. `Carver II' showed increases in FCGR up to 11 wk after transplanting then rapidly declined while `Rojo-Blanco' and TU-1892 began to decline 8 and 6 wk after transplanting, respectively. RCGR showed rapid increases (100 g.m /area/week) and (150 g/m /area/week) for early and late maturing cultivars beginning 6 wk after transplanting and this increase continued until the 12th and 8 th wk after transplanting for early and late maturing cultivars, respectively. Cultivars from both maturity groups began to produce surplus assimilates (Alpha a) 6 wk after transplanting. which coincided with the rapid increases in RCGR at the same time. Thus indicating that storage root enlargement begins after the plant had accumulated a surplus of assimilates.

scholarly journals Physiological responses of two tropical weeds to shade: I. Growth and biomass allocation

1999 ◽  
Vol 34 (6) ◽  
pp. 944-952 ◽  
Author(s):  
Moacyr Bernardino Dias-Filho
Keyword(s):  
Leaf Area ◽  
Weed Management ◽  
Dry Mass ◽  
High Light ◽  
Low Light ◽  
Light Regimes ◽  
Leaf Dry Mass ◽  
Lower Ability ◽  
Total Plant ◽  
Plant Dry Mass

Ipomoea asarifolia (Desr.) Roem. & Schultz (Convolvulaceae) and Stachytarpheta cayennensis (Rich) Vahl. (Verbenaceae), two weeds found in pastures and crop areas in Brazilian Amazonia, were grown in controlled environment cabinets under high (800-1000 µmol m-² s-¹) and low (200-350 µmol m-² s-¹) light regimes during a 40-day period. For both species leaf dry mass and leaf area per total plant dry mass, and leaf area per leaf dry mass were higher for low-light plants, whereas root mass per total plant dry mass was higher for high-light plants. High-light S. cayennensis allocated significantly more biomass to reproductive tissue than low-light plants, suggesting a probably lower ability of this species to maintain itself under shaded conditions. Relative growth rate (RGR) in I. asarifolia was initially higher for high-light grown plants and after 20 days started decreasing, becoming similar to low-light plants at the last two harvests (at 30 and 40 days). In S. cayennensis, RGR was also higher for high-light plants; however, this trend was not significant at the first and last harvest dates (10 and 40 days). These results are discussed in relation to their ecological and weed management implications.

Propanil Resistance in Populations of Junglerice (Echinochloa colona) in Colombian Rice Fields

Weed Science ◽  
1993 ◽  
Vol 41 (2) ◽  
pp. 201-206 ◽  
Author(s):  
Albert J. Fischer ◽  
Eduardo Granados ◽  
Diego Trujillo
Keyword(s):  
Leaf Area ◽  
Reproductive Parameters ◽  
Considerable Variability ◽  
Relative Growth ◽  
Mean Relative Growth Rate ◽  
Previously Treated ◽  
Ecological Success ◽  
Net Assimilation ◽  
Susceptible Populations ◽  
Different Levels

Dose-response studies estimating GR40 values indicated different levels of propanil resistance in junglerice populations from fields previously treated with propanil, compared to a check population collected where this herbicide had never been used. The GR40 for susceptible populations ranged from 0.36 to 0.50 kg ai ha−1and for resistant populations ranged from 1.10 to 3.10 kg ai ha−1. Considerable variability in growth and morphology existed among populations. Variability in cumulative leaf area, aboveground biomass, mean relative growth rate, mean net assimilation rate, and mean leaf area ratio could not be related to propanil resistance. Competitiveness was not related to propanil resistance either. of several vegetative and reproductive parameters measured at maturity, only grain weight per plant and number of grains per plant were correlated with GR40 (r = −0.73, P = 0.06). This trend towards lower reproductive fitness in propanil-resistant junglerice plants may reduce its ecological success when growing with propanil-susceptible plants in the absence of this herbicide.

Invasion by Pittosporum undulatum of the Forests of Central Victoria. III. Effects of Temperature and Light on Growth and Drought Resistance

1982 ◽  
Vol 30 (3) ◽  
pp. 347 ◽  
Author(s):  
RM Gleadow ◽  
KS Rowan
Keyword(s):  
Leaf Area ◽  
Photon Flux ◽  
First Year ◽  
Low Light ◽  
Relative Growth ◽  
Relative Growth Rates ◽  
Drought Tolerant ◽  
Deep Shade ◽  
Net Assimilation ◽  
Shade Plants

The clumping of invading seedlings of Pittosporum undulatum Vent. around the butts of established trees is due partly to the site-dependent survival of seedlings. particularly during summer. P. undulatum seedlings were very drought-tolerant when grown at moderately low temperatures (21.4°C day/17.8°C night compared with 27.4°C day/23.9°C night) and in deep shade. Plants droughted at 5°C higher temperatures and higher photon flux densities stopped transpiring and wilted 10-13 days earlier than those droughted under cooler, densely shaded conditions. Well watered seedlings had higher relative growth rates and net assimilation rates when grown under higher temperatures and photon flux densities. Control seedlings were more leafy when grown under low light. as reflected by the specific leaf area, leaf area ratio and root/shoot ratios. The adverse effects of higher photon flux densities and temperatures on the drought tolerance of P. undulatum seedlings support the hypothesis that survlval of invading seedlings in their first year is dependent on the microclimate.

scholarly journals Growth analyses of tomato genotypes grown under low energy conditions.

1991 ◽  
Vol 39 (3) ◽  
pp. 191-196 ◽  
Author(s):  
M. Nieuwhof ◽  
F. Garretsen ◽  
J.C. van Oeveren
Keyword(s):  
Leaf Area ◽  
Weight Ratio ◽  
Energy Conditions ◽  
Genotypic Differences ◽  
Low Light ◽  
Strong Negative Correlation ◽  
Plant Weight ◽  
Relative Growth ◽  
Net Assimilation ◽  
Growth Analyses

Growth analyses were carried out on young plants of 15 genotypes, grown initially at 19/14 degrees C day/night temperatures for an 8 h day at low light intensity and subsequently at the night temperatures of 6, 10 and 14 degrees C. Significant genotypic differences occurred for relative growth rate (RGR), net assimilation rate (NAR), leaf area ratio (LAR), specific leaf area (SLA) and leaf weight ratio (LWR). RGR, LAR and SLA increased and LWR decreased at higher night temperatures. A strong negative correlation was observed between NAR and LAR and NAR and SLA whilst a positive correlation was noted between LAR and SLA. Plant weight was strongly influenced by seed size. (Abstract retrieved from CAB Abstracts by CABI’s permission)

scholarly journals Conditioning Affects Growth and Drought Tolerance of Cucurbit Transplants

1994 ◽  
Vol 119 (5) ◽  
pp. 943-948 ◽  
Author(s):  
Joyce G. Latimer ◽  
Reuben B. Beverly
Keyword(s):  
Water Loss ◽  
Citrullus Lanatus ◽  
Moisture Stress ◽  
Plant Performance ◽  
Stem Length ◽  
Relative Growth ◽  
Detached Leaves ◽  
Dry Down ◽  
Mean Relative Growth Rate ◽  
The Mean

Brushing (40 strokes per 1.5 minutes, twice daily) or moisture stress conditioning (MSC) (daily nonlethal dry-down cycles) reduced seedling growth of two cucumber (Cucumis sativus L.) cultivars in 1991 and three squash (Cucurbita pepo L.) cultivars in 1991 and 1992. In both years, watermelon [Citrullus lanatus Thunb. (Matsum. & Nakai)] cultivars varied in responsiveness to brushing; brushing reduced stem length 0% to 44% over four cultivars in 1992. MSC reduced growth of all cultivars. Brushing increased the rate of water loss from detached leaves of cucumber, squash, and watermelon, whereas MSC decreased water loss from leaves of cucumber and squash. In 1991, under well-watered posttransplant conditions, MSC increased the mean relative growth rate (RGR) of cucumber and watermelon transplants in the greenhouse. Brushing increased the RGR of watermelon transplants. In 1992, MSC increased the RGR of squash and watermelon transplants grown under posttransplant drought-stressed conditions, while brushing had no effect. Both conditioning treatments controlled plant growth in the greenhouse without diminishing subsequent plant performance.

scholarly journals BUDIDAYA BEBERAPA VARIETAS IKAN SEPAT RAWA (Trichogaster trichopterus Pall) DENGAN PEMBERIAN PAKAN KOMERSIAL (SOME VARIETY AQUACULTURE THREE SPOT GORAMY (TRICHOGASTER TRICHOPTERUS PALL) WITH THE PROVISION OF COMMERCIAL FEED)

2016 ◽  
Vol 1 (2) ◽  
pp. 214 ◽  
Author(s):  
Akhmad Murjani
Keyword(s):  
Growth Rate ◽  
Tidal Marshes ◽  
Average Growth Rate ◽  
Average Growth ◽  
Relative Growth ◽  
Growth And Survival ◽  
Commercial Feed ◽  
Mean Relative Growth Rate ◽  
The Mean ◽  
Cultivation Environment

Tujuan dari penelitian ini adalah untuk menentukan kecepatan pertumbuhan dan kelangsungan hidup tiga jenis ikan gurami (Trichogaster trichopterus, Pall) di rawa monoton, rawa pasang surut, dan rawa tadah hujan yang dipelihara di hapa Galam.Tiga jenis ikan gurami (Trichogaster trichopterus, Pall) mampu hidup dan beradaptasi di lingkungan budidaya, dan dapat diberi makan dengan pakan buatan seperti ikan budaya. Variasi jenis ikan tidak  signifikan mempengaruhi pertumbuhan rawa dan kelangsungan hidup ikan yang dipelihara di lingkungan budidaya rawa. Tingkat pertumbuhan berat rata-rata relatif terbaik adalah perlakuan C (ikan  gurami rawa tadah hujan) sebesar 29.36%. Tingkat pertumbuhan pangjang rata-rata relatif terbaik adalah perlakuan B (Ikan gurami padang rumput rawa) sebesar 9,35%. Konversi pakan terbaik terdapat pada perlakuan C (ikan gurami dari tadah hujan) sebesar 6.80. Tingkat keangsungan hidup terbaik terdapat pada perlakuan B, C, D yaitu sebesar 75.56%.The purpose of this study was to determine the speed of growth and survival of several varieties of three spot goramy (Trichogaster trichopterus Pall) from the monotonous marshes, tidal marshes, bogs and swamps rainfed fields that are kept in hapa Galam.Three spot goramy (Trichogaster trichopterus Pall) are able to live and adapt in the cultivation environment, and can be fed with artificial feed like most culture fish. Variations in the type of fishes did not significantly affect marsh growth and survival of fish that are kept in swamp ride cultivation environment. The mean relative growth rate of weight it is best to treatment C (fish from the marsh three spot goramy rainfed) of 29.36%. Average growth rate is relatively long it is best to treatment B (three spot goramy of marsh meadow Galam) for 9.35 %. Conversion is best to feed on the C treatment (fish from the marsh three spot goramy rainfed) of 6.80. the best survival was in treatment B, C, D of 75.56%.

Aphid-induced changes in growth indices of three leguminous plants: unrestricted infestation

1985 ◽  
Vol 63 (12) ◽  
pp. 2454-2459 ◽  
Author(s):  
C. D. B. Hawkins ◽  
M. J. Aston ◽  
M. I. Whitecross
Keyword(s):  
Acyrthosiphon Pisum ◽  
Growth Patterns ◽  
Relative Growth ◽  
Relative Growth Rates ◽  
Unit Leaf ◽  
Aphis Craccivora Koch ◽  
The Mean ◽  
Net Assimilation ◽  
Induced Changes ◽  
And Control

The effects of various densities of cowpea aphids (Aphis craccivora Koch) and pea aphids (Acyrthosiphon pisum Harris), both Homoptera: Aphididae, on the growth of cowpea (Vigna unguiculata (L.) Walp. cv. Caloona), broad bean (Vicia faba L. cv. Aquadulce), and garden pea (Pisum sativum L. cv. Victory Freezer) seedlings were investigated. Within 10 days of infestation, aphid feeding significantly reduced plant dry weights and mean relative growth rates for the six plant–aphid combinations. In all cases except one, the mean unit leaf or net assimilation rate was also significantly reduced within 10 days. The mean leaf area ratio was the same for infested and control plants. The aphid-induced changes in host plants appear to be due to changes in photosynthesis, respiration, and translocate removal from the phloem over the 10-day period. Changes in the growth patterns of the host plant within this period are similar, but the underlying physiological effects could vary among particular plant–aphid combinations.

Perturbed Leaf Development in Sorghum bicolor Exposed to Salinity: a Marker of Transition Towards Adaptation

1993 ◽  
Vol 20 (2) ◽  
pp. 243 ◽  
Author(s):  
H Seligmann ◽  
GN Amzallag ◽  
HR Lerner
Keyword(s):  
Sorghum Bicolor ◽  
Leaf Development ◽  
High Salinity ◽  
Adaptation Period ◽  
Adaptation Process ◽  
Relative Growth ◽  
Adaptation Response ◽  
Mean Relative Growth Rate ◽  
The Mean ◽  
Developmental Window

Pretreatment for 3 weeks with NaCl, within the range 35-150 mol m-3, of 8 day old Sorghum bicolor cv. 610, results in adaptation of the plants to high salinity; plants become tolerant to 300 mol m-3 NaCl, which is lethal for unadapted plants. During the adaptation period one or more developmentally perturbed leaves (DPL) may occur. DPL formation is positively correlated with the mean relative growth rate (RGR) of the plant following exposure to 300 mol m-3 NaCl, which reflects the degree of adaptation to high salinity. Treatments with exogenous phytohormones affect both DPL formation as well as the adaptation response. When plants 14 days old or more are exposed to salinity, neither adaptation nor DPL formation occurs, demonstrating the existence of a developmental window during which these phenomena may take place. These data suggest that DPL does not result from salt damage to the plant, but rather that it should be considered as a marker of the adaptation process.

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