Régulations hydriques comparées de populations de Rumex acetosella le long d'un gradient successionnel postcultural

1990 ◽  
Vol 68 (2) ◽  
pp. 428-434 ◽  
Author(s):  
Josep Escarré ◽  
Claudie Houssard ◽  
Nicole Vartanian

Two sets of plants of Rumex acetosella L. of known sex (males and females in the same proportions), belonging to populations from two fields that were abandoned 2 and 15 years ago, were grown on soil regularly watered to field capacity or to half of field capacity. Four harvests of six plants for each sex, population and treatment were performed to follow the changes in biomass allocation to aerial and subterranean organs as related to plant water potential. In well-watered plants, the old population had a higher rate of water use than the young one because of rapid leaf surface area development and a higher root/shoot biomass ratio, which should make it more competitive in situations of strong interspecific competition, such as the late stages of succession. When plants were subjected to water stress (half of field capacity), clear-cut differences appeared between males and females at the vegetative stage. Female plants showed a good regulation of water balance and reached higher biomass values than male plants. However, flowering and fruiting induced a decrease in the root/shoot biomass ratio and in the transpiration rate of female plants, which would tend to exclude them with time. These results may explain the fact the the oldest Rumex acetosella communities consist predominantly of males.

Weed Science ◽  
2011 ◽  
Vol 59 (3) ◽  
pp. 335-340 ◽  
Author(s):  
Karen J. Kennedy ◽  
Nathan S. Boyd ◽  
Vilis O. Nams ◽  
A. Randall Olson

Sheep sorrel is an invasive, creeping perennial weed of lowbush blueberry fields that decreases yields and hinders harvest. Much of the basic phenology of sheep sorrel in blueberry fields is unknown and not documented in peer-reviewed journals. Three levels of fertilizer (0, 20, and 40 kg N ha−1) and two levels of hexazinone (0 and 1.92 kg ai ha−1) were applied to three vegetative-year blueberry fields to determine their effects on root and shoot growth, biomass allocation, and seed production of sheep sorrel plants. Hexazinone efficacy varied widely between sites, but suppressed shoot biomass, achene number and weight, and reproductive biomass, as well as the reproductive : shoot biomass ratio. Fertilizer tended to increase achene number and increased sheep sorrel shoot biomass in the absence of hexazinone, but had no effect on achene weight, root biomass, or reproductive biomass. When fertilizer was applied, sheep sorrel allocated resources to sexual reproduction at the expense of vegetative growth.


2019 ◽  
Vol 40 (3) ◽  
pp. 1101
Author(s):  
Caio César Silva Alvarenga Correia ◽  
Fernando França da Cunha ◽  
Everardo Chartuni Mantovani ◽  
Derly Jose Henriques Silva ◽  
Santos Henrique Brant Dias ◽  
...  

The region of the Zona da Mata of Minas Gerais stands out in the production of vegetables. To achieve the success in this activity, it is important to choose suitable cultivars and apply irrigation correctly. This study aimed to determine the optimum irrigation depth and evaluate new commercial arugula cultivars in the Zona da Mata of Minas Gerais. The cultivation was carried out in a greenhouse during three cycles with periods of 33 (January 11, 2016 to February 12, 2016), 36 (March 1, 2016 to April 5, 2016), and 36 (April 12, 2016 to May 17, 2016) days. The experimental design was a randomized complete block design with five replications, five irrigation depths (50, 75, 100, 125, and 150% of the crop evapotranspiration-ETc) in the plots, and three arugula cultivars (Antonella, Cultivada, and Folha Larga) in the subplots. A drip irrigation system was used. The parameters evaluated were root depth, root fresh mass, plant water potential, leaf temperature, number of commercial leaves, total number of plants, fresh shoot mass, and water use efficiency. Arugula cultivars did not present differences in their agronomic characteristics. An irrigation depth of the 50% ETc is recommended if the soil moisture is under the field capacity at the beginning of the arugula cycle.


Author(s):  
Patrik BURG ◽  
Jana BURGOVÁ ◽  
Vladimír MAŠÁN ◽  
Miroslav VACHŮN

Experimental measurements focused on evaluation of grapevine leaf surface area development in nine varieties, in the viticultural conditions of South Moravia. The dynamics of leaf surface area development was measured by using a device called leaf area meter AM 300. The device operates on the principle of a scanner and the resulting values are expressed through the leaf area index - LAI. The measurements were carried out in five dates during phenophases of growth, flowering, initial development of fruits, and ripening of berries. The results show a significant differences in increase in leaf area between the evaluated varieties, especially during flowering. The size of the leaf area, depending on the year, corresponds to values between 7.615 and 13.483 square metres per hectare. The largest leaf area was reached in growth stage 8, which is ripening of fruit. The leaf area reached the largest size in the varieties Grüner Veltliner, Zweigelt, and Sauvignon, with values ranging from 20.560 to 26.481 square metres per hectare. The results suggest that a significant proportion of leaf area is also represented by lateral shoots whose size in the ripening phase, depending on variety, ranges from 33.7 to 52.9 per cent of the total leaf area.


1982 ◽  
Vol 60 (8) ◽  
pp. 1885-1891 ◽  
Author(s):  
David A. Boag

Japanese quail (Coturnix coturnix) acquire an ability to dominate conspecifics of the same sex through inheritance and through experience during interactions with siblings of the same sex. The extent to which the former can mask the latter was investigated in both males and females of this species. The results suggest that when differences in dominance status of the parental stock are marked (winning >85% of interactions versus winning <25%) the ability to dominate, acquired through inheritance, overrides virtually all ability acquired through experience in the brood. All encounters among males were decisively won by young birds from dominant stock, whereas among females the results, although similar, were not as clear-cut. The production of young by the two parental stocks was compared; those of low dominance status produced both greater numbers of young as well as a significantly higher proportion surviving to adulthood.


1994 ◽  
Vol 24 (5) ◽  
pp. 1029-1032 ◽  
Author(s):  
B.J. Hawkins ◽  
S. McDonald

A 3 × 2 factorial experiment was conducted to investigate the interaction of temperature and soil water status on the growth, photosynthetic, transpiration, and nitrogen fixation rates of 2-month-old red alder (Alnusrubra Bong.) seedlings. Three day: night temperature treatments, 15:10 °C, 20:10 °C, and 25:10 °C were used. Two soil-water treatments kept pots between 85 and 100% of field capacity (wet) and 70–85% of field capacity (dry). Treatment effects on growth, net photosynthetic, transpiration and nitrogen fixation rates, plant water potential, and foliar nutrient concentration were measured over a 9-week period. The greatest seedling growth occurred at 25 °C day temperatures, while 20 and 25 °C days produced the greatest nodule growth. The allocation of biomass to roots increased with decreasing temperature. The highest rates of net photosynthesis occurred at 15 and 20 °C whereas transpiration was greatest at 25 °C. Plant water stress was greatest at 25 °C. The difference in plant water potential between the wet and dry treatments was only 0.04 MPa, which was not great enough to produce significant effects on growth or photosynthesis. Nitrogen fixation rates were highest in the wet treatment seedlings at 20 and 25 °C.


Irriga ◽  
2018 ◽  
Vol 21 (3) ◽  
pp. 605
Author(s):  
Otavio Bagiotto Rossato ◽  
Carlos Alexandre Costa Crusciol ◽  
Jorge Martinelli Martello

FITOMASSA E ACUMULO DE MACRONUTRIENTES EM CANA-DE-AÇÚCAR SOB COMPACTAÇÃO E UMIDADE DO SOLO  OTAVIO BAGIOTTO ROSSATO1; JORGE MARTINELLI MARTELLO2; CARLOS ALEXANDRE COSTA CRUSCIOL3  1Professor do Instituto Federal Catarinense, CEP 89700-000, Concórdia, SC, Brasil.E-mail: [email protected] em Agronomia – Energia na Agricultura, Faculdade de Ciências Agronômicas, Universidade Estadual Paulista (UNESP), CEP 18610-307, 237, Botucatu, SP, Brasil.E-mail: [email protected] do Departamento de Produção e Melhoramento Vegetal, Faculdade de Ciências Agronômicas, Universidade Estadual Paulista (UNESP), CEP 18610-307, 237, Botucatu, SP, Brasil. E-mail: [email protected]  1 RESUMO O experimento foi realizado em tubos de PVC, em casa de vegetação, usando um delineamento de blocos ao acaso, com quatro repetições, com tratamentos arranjados em esquema fatorial (4x3x2), equivalente a quatro variedades, 3 níveis de compactação do solo na camada de 0,20 a 0,30 m (1,35; 1,45 e 1,55 Mg m-3) e 2 teores de água no solo (70% e 90% da capacidade de campo). Aos 72 dias após emergência da plantas foram avaliadas a massa seca de raízes e parte aérea e os teores de N, P, K, Ca, Mg, S acumulados na parte aérea da cana-de-açúcar. O maior nível de umidade no solo propiciou aumento na produção de matéria seca de raiz e da parte aérea além de maior acúmulo de N, P, K, Ca, Mg e S na parte aérea da cana-de-açúcar, independentemente da variedade e nível de compactação. Além disso, na variedade RB72454 obteve-se maior produção de matéria seca da parte aérea e maior acúmulo de N, P, K, Ca, Mg e S que as demais variedades quando sob maior disponibilidade de água no solo. O maior nível de compactação do solo promoveu redução na produção de matéria seca da parte aérea e no acúmulo de N, P, K, Ca e Mg na parte aérea da cana-de-açúcar, independentemente da variedade utilizada. Em solos com menor disponibilidade de água (70%CC), o maior nível de compactação do solo (1,55 Mg m-3) promoveu redução na produção de biomassa da parte aérea e no acúmulo de N, P, K, Ca e Mg.  Palavras-Chaves: Saccharum spp, teor de água no solo, densidade, matéria seca, raiz, nutrientes, parte aérea.  ROSSATO, O. B.; MARTELLO, J. M.; CRUSCIOL, C. A. C.DRY MATTER PRODUCTION AND MACRONUTRIENT ACCUMULATION IN SUGARCANE GROWN UNDER LEVELS OF COMPACTION AND SOIL MOISTURE      2 ABSTRACT The experiment was conducted in PVC tubes, in a greenhouse, using a randomized block design with four replications, in a factorial arrangement (4x3x2) equivalent to four varieties, three levels of soil compaction in the layer 0.20 to 0.30 m (1.35, 1.45 and 1.55 Mg m-3) and two soil moisture contents (70% and 90% of field capacity). 72 days after the plants emergence the dry mass of roots and shoots and N, P, K, Ca, Mg, S contents accumulated in shoots of sugarcane were assessed. The results show that the higher moisture level in the soil led to increases in dry matter production of shoots and roots besides higher accumulation of N, P, K, Ca, Mg and S in sugarcane shoots regardless of the variety and level of compaction. In addition, variety RB72454 provided greater shoots with dry matter and higher accumulation of N, P, K, Ca, Mg and S on shoots than in other varieties under greater availability of water in the soil. The highest level of soil compaction promoted reduction in shoot dry matter production and accumulation of N, P, K, Ca and Mg on shoots of sugarcane regardless of the variety used. On soils with lower water availability (70% of field capacity), the highest level of soil compaction (1.55 Mg m-3) promoted a reduction on shoot biomass production and accumulation of N, P, K, Ca and Mg. Keywords: Saccharum spp, soil water content, density, dry matter, root, nutrients, shoot.


Author(s):  
M. W. Lestari ◽  
N. Farita ◽  
A. Sharma ◽  
B. Purkait

Plants that experience drought stress protects themselves through several mechanisms namely avoidance, tolerance, recovery, and escape. Eight varieties of yardlong bean plants were subjected to a drought stress at the rates of 50% of the field capacity (FC) and 100% of the field capacity (FC). The results showed that yardlong bean plants possessed the mechanisms of escape, demonstrated by the increase in Peroxidase (POX) enzyme activity. Avoidance was demonstrated by the reduced evapotranspiration surface of the decreased leaf surface area, and the increased number of closed stomata. Tolerance was demonstrated by the increased proline accumulation.


1988 ◽  
Vol 66 (4) ◽  
pp. 757-761 ◽  
Author(s):  
Lisa J. Cerligione ◽  
Anthony E. Liberta ◽  
Roger C. Anderson

Nonmycorrhizal little-bluestem plants grown in sterile soil and mycorrhizal plants grown in unsterilized soil were experimentally subjected to varied soil moisture conditions that ranged from saturation for 12 h followed by drainage for 48 h to allowing soil to dry to permanent wilting point and returning it to field capacity 72 h later. Nonmycorrhizal plants produced significantly (p < 0.05) greater root and shoot biomass, had lower root/shoot ratios, and produced more flowering culms than mycorrhizal plants. However, mycorrhizal plants had significantly higher tissue concentrations of phosphorus, calcium, zinc, iron, copper, aluminum, and sodium and lower concentrations of potassium amd manganese. There was a decrease in percent colonization as soil water availability decreased.


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