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Concentrations of Abscisic Acid and Indoleacetic Acid in Cotton Fruits and Their Abscission Zones in Relation to Fruit Retention

Guinn, Gene; Brummett, Donald L.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /01/1987 Português
Relevância na Pesquisa
17.11584%
An experiment was conducted with field-grown cotton (Gossypium hirsutum L.) to determine the effects of drought and an increase in available photosynthate on the abscisic acid (ABA) and indoleacetic acid (IAA) contents of 3-day-old bolls and their abscission zones. Photosynthate availability was manipulated by removing about two-thirds of the plants to permit increased irradiance, and thus photosynthesis, in the plant canopy. The demand for photosynthate was decreased by removing all bolls from the remaining plants. The thinning and defruiting operations were performed about 3 weeks after first flower. Control plants were neither thinned nor defruited. Effects of water deficit were observed by making three harvests at different times during a 2-week irrigation cycle. Increasing the availability of photosynthate increased boll retention, but had relatively little effect on the concentrations of ABA and IAA in bolls. However, it did increase the concentration of IAA in abscission zones. Water deficit increased the ABA content of bolls and abscission zones and decreased the IAA content of bolls and abscission zones. Across all treatments, the IAA content of abscission zones was positively correlated, and the ABA content of bolls was negatively correlated...

Abscisic Acid and Cutout in Cotton

Guinn, Gene
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /01/1985 Português
Relevância na Pesquisa
17.11584%
A decline in growth, flowering, and boll (fruit) retention is referred to as cutout in cotton (Gossypium hirsutum L.). Fruit load affects cutout, possibly through hormonal effects. Experiments were conducted to test the hypothesis that fruits are a source of abscisic acid (ABA) that moves into fruiting branches and growing points where it inhibits growth, flowering, and boll retention. Removal of the flower or young boll at the first node of fruiting branches did not decrease the ABA content of fruiting branches or the abscission zone at the second node. Effects on ABA content of the boll at the second node varied. In one field test, ABA content of bolls at the second node decreased with successive harvests as bolls were removed from first node positions of several fruiting branches. Thus, the effect was cumulative and was not limited to individual branches. Removal of the flower or boll at the first node increased boll retention at the second node. Removal of all flowers during the first 3 weeks of flowering delayed the decreases in growth, flowering, and boll retention that occurred as fruit load increased. But, the ABA content of fruiting branches and mainstem apices was not decreased by early defruiting and did not increase with increasing fruit load. The results do not support the hypothesis that fruits are a source of ABA that moves into fruiting branches and growing points where it then inhibits growth...

Intensidade de raleio de frutos em pessegueiro flordaprince conduzidos em pomar com alta densidade de plantio.

SCARPE FILHO, J.A.; MINAMI, K.; KLUGE, R.A.
Fonte: Pesquisa Agropecuaria Brasileira, Brasilia, v.35, n.6, p.1109-13, jun.2000. Publicador: Pesquisa Agropecuaria Brasileira, Brasilia, v.35, n.6, p.1109-13, jun.2000.
Tipo: Artigo em periódico indexado (ALICE)
Português
Relevância na Pesquisa
17.11584%
O objetivo deste trabalho foi verificar o comportamento de pessegueiros (Prunus persica (L.) Batsch.) cultivar Flordaprince, conduzidos em pomar com alta densidade (3.333 plantas/ha), submetidos a diferentes intensidades de raleio manual de frutos. Os tratamentos utilizados foram 120, 100 e 80 frutos por planta, e o controle sem raleio (230 frutos por planta). As plantas submetidas ao raleio produziram frutos significativamente maiores e mais pesados do que os do controle. A produção por planta (kg) e a produtividade estimada (t/ha) foram maiores nas plantas sem raleio, mas a classificação comercial e a receita bruta (R$/ha) desse tratamento foram menores, devido ao menor tamanho e peso dos frutos. Os tratamentos 100 e 80 frutos por planta (56,52% e 65,21% de raleio, respectivamente) apresentaram os melhores resultados.; 2000