Base temperature and thermal time requirements for germination and emergence of temperate pasture species

Moot, Derrick J.; Scott, W. R.; Roy, Anjali; Nicholls, A. C.

doi:10.1080/00288233.2000.9513404

Cited by 124 publications

(134 citation statements)

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“…Esse declínio de T b com o aumento da fração percentual não foi observado no presente trabalho, pois, como já mencionado, frações maiores não puderam ser consideradas. Temperatura base ao redor de 19 ºC pode ser considerada relativamente elevada se comparada, por exemplo, com espécies de clima temperado como Trifolium repens L., Lolium perenne L. e Cichorium intybus L., cujas T b foram, respectivamente, 0 ºC, 3.7 ºC e 1.2 ºC (Moot et al 2000). Mesmo algumas espécies invasoras de culturas comuns no Estado de São Paulo, como Sida cordifolia L., S. glaziovii K.Schum.…”

Section: Resultsunclassified

“…De acordo com a literatura, temperaturas sub-ótimas podem tanto inibir (Moot et al 2000), como não afetar a germinabilidade (Larsen & Bibby 2005). Esses últimos autores reportam que, se a germinabilidade é inibida em temperaturas infra-ótimas, isso deve indicar que T b varia dentro da população, a menos que o experimento tenha terminado antes da germinação se completar.…”

Section: Resultsunclassified

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Dependência térmica da germinação de sementes de Drymaria cordata (L.) Willd. ex Roem. & Schult. (Cariophyllaceae)

Cardoso

2009

Acta Bot. Bras.

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RESUMO -(Dependência térmica da germinação de sementes de Drymaria cordata (L.) Willd. ex Roem. & Schult. (Cariophyllaceae)). A temperatura representa um importante fator ambiental regulador da germinação de sementes. Procurou-se avaliar a resposta de sementes de D. cordata à temperatura, com base no modelo de graus-dia, testando-se assim a eficiência desse modelo em descrever o comportamento germinativo da semente em diferentes regimes térmicos. Testou-se também a resposta das sementes à luz, concluindo-se que a luz branca promove a germinação. As temperaturas mínima, ótima e máxima de germinação foram, respectivamente, 17,1, 26 e 33,4 °C. Considerando-se que a velocidade de germinação de D. cordata variou com a temperatura numa relação aproximadamente linear, o modelo de graus-dia pode ser uma ferramenta válida para se estudar a dependência da temperatura da germinação dessas sementes. Uma possível aquisição de dormência durante a incubação isotérmica pode exigir a aplicação de outros modelos que descrevam melhor o comportamento germinativo de D. cordata em diferentes regimes térmicos. Palavras-chave: fotoblastismo, graus dia, planta invasora, temperaturaABSTRACT -(Thermal-dependence of seed germination in Drymaria cordata (L.) Willd. ex Roem. & Schult. (Cariophyllaceae)). Temperature is an important environmental factor controlling seed germination. The temperature response of D. cordata seeds was assessed on a thermal time basis in order to evaluate this model describing germination behavior of the seeds under different thermal regimes. Seed response to light was also tested, and the results led to the conclusion that germination was promoted by white light. Base, optima and ceiling temperatures for germination of D. cordata were, respectively, 17.1 °C, 26 °C and 33.4 °C. Since germination rate was linearly related to temperature, the thermal time model can be used to assess temperature dependence of seed germination in D.cordata. Possible acquisition of seed dormancy during imbibition may not allow a good fit of cumulative germination under some temperature regimes, and other models must be used.

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Section: Resultsunclassified

Dependência térmica da germinação de sementes de Drymaria cordata (L.) Willd. ex Roem. & Schult. (Cariophyllaceae)

Cardoso

2009

Acta Bot. Bras.

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“…Em julho, as temperaturas foram baixas e críticas para o desenvolvimento do cornichão, visto que, em alguns dias, foram inferiores à temperatura-base da espécie, de 4,7°C (Moot et al, 2000). Essas temperaturas baixas, além do próprio manejo imposto, atrasaram a realização do último corte em 43 dias.…”

Section: Resultsunclassified

Caracterização agronômica de genótipos de cornichão (Lotus corniculatus L.)

Soster¹,

Scheffer-Basso

Dall'Agnol

et al. 2004

R. Bras. Zootec.

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RESUMO -Este trabalho foi conduzido com o objetivo de caracterizar agronomicamente genótipos de cornichão (Lotus corniculatus L.), incluindo oito populações do cv. São Gabriel, um cultivar rizomatoso (cv. ARS-2620) e um cultivar sem rizomas (cv. Trueno). Plantas individuais foram cultivadas e submetidas a sete cortes em condições de campo, durante um ano, em Passo Fundo, Rio Grande do Sul, Brasil. Os genótipos apresentaram variabilidade quanto ao comprimento de entrenós, estatura, diâmetro, comprimento de legumes, produção de forragem e valor nutritivo. Na média geral, as populações e o cv. Trueno foram cerca de 50% mais produtivos em relação ao cv. ARS-2620. Os genótipos apresentaram entre 80 e 100% de sobrevivência. O conteúdo de proteína bruta reduziu de 21,8% (estádio vegetativo) para 11,2% (estádio de frutificação). A média geral de fibra detergente ácido foi de 24,2% e a de fibra detergente neutro variou entre 55,3 e 58,8%.Palavras-chave: forragem, rizomatoso, valor nutritivo Agronomic Characterization if Birdsfoot Trefoil Genotypes (Lotus corniculatus L.)ABSTRACT -This work was carried out to characterize agronomically birdsfoot trefoil (Lotus corniculatus L.) genotypes, including eight populations derived from the cultivar São Gabriel, one rhizomatous cultivar (ARS-260) and one cultivar without rhizomes (Trueno). Individual plants were submitted to seven cuts under field conditions during one year, at Passo Fundo, Rio Grande do Sul, Brazil. The genotypes showed variability relative to internode lenght, height, diameter, legume lenght, forage production and nutritive value. On the average, the populations and the cv. Trueno were about 50% more productive than the cv. ARS-260. The genotypes presented a survival range from 80% to 100%. The crude protein content decreased from 21.8 (vegetative stage) to 11.2% (fruiting stage). The overall mean for acid detergent fiber was 24.2% and the neutral detergent fiber ranged from 55.3% to 58.8%.

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“…To calculate P, a thermal time methodology was used with the base temperature and leaf appearance interval for ryegrass taken from subsequent New Zealand studies [39,40] as being 2.0˝C and 101˝C¨d, respectively. Daily maximum and minimum temperature data for Palmerston North weather station NAN3238, approximately 1 km distant from the experiment site were downloaded from the 'Cliflo' online database of the New Zealand National Institute of Water and Atmospheric Research Ltd. (Auckland, New Zealand).…”

Section: Mechanistic Modeling Of Phytomer Root Productionmentioning

confidence: 99%

Do Phytomer Turnover Models of Plant Morphology Describe Perennial Ryegrass Root Data from Field Swards?

2016

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Abstract:This study aimed to elucidate seasonal dynamics of ryegrass root systems in field swards. Established field swards of perennial ryegrass with white clover removed by herbicide and fertilised with nitrogen (N) to replace clover N fixation were subjected to lax and hard grazing management and root biomass deposition monitored using a root ingrowth core technique over a 13 month period. A previously published phytomer-based model of plant morphology that assumes continuous turnover of the root system was used to estimate mean individual root weight (mg) not previously available for field swards. The predicted root weights compared credibly with root data from hydroponic culture and the model output explained much of the seasonal variation in the field data. In particular, root deposition showed a seasonality consistent with influence of an architectural signal (AS) determined by plant morphology. This AS arises because it is theoretically expected that with rising temperatures and decreasing phyllochron in early summer, more than one leaf on average would feed each root bearing node. Conversely, in autumn the reverse would apply and root deposition is expected to be suppressed. The phytomer-based model was also able to explain deeper root penetration in summer dry conditions, as seen in the field data. A prediction of the model is that even though total root deposition is reduced by less than 10% under hard grazing, individual root weight is reduced proportionately more because the available substrate is being shared between a higher population of tillers. Two features of the field data not explained by the phytomer based model, and therefore suggestive of hormonal signaling, were peaks of root production after summer drought and in late winter that preceded associated herbage mass rises by about one month. In summary, this research supports a view that the root system of ryegrass is turning over on a continuous basis, like the leaves above ground. The phytomer based model was able to explain much of the seasonal variation in root deposition in field swards, and also predicts a shift of root deposition activity, deeper in summer and shallower in winter.

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Base temperature and thermal time requirements for germination and emergence of temperate pasture species

Cited by 124 publications

References 14 publications

Dependência térmica da germinação de sementes de Drymaria cordata (L.) Willd. ex Roem. & Schult. (Cariophyllaceae)

Dependência térmica da germinação de sementes de Drymaria cordata (L.) Willd. ex Roem. & Schult. (Cariophyllaceae)

Caracterização agronômica de genótipos de cornichão (Lotus corniculatus L.)

Do Phytomer Turnover Models of Plant Morphology Describe Perennial Ryegrass Root Data from Field Swards?

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