Qualidade fisiológica e armazenamento de sementes de algodão embebidas em solução de cloreto de mepiquat

Abstract

RESUMOApós tratamento de sementes, é comum a semeadura não ocorrer imediatamente. Eeste trabalho, objetivou-se determinar o efeito do armazenamento de sementes de algodão embebidas com regulador de crescimento Cloreto de Mepiquat (CM) na qualidade fisiológica e manutenção do seu efeito como fitorregulador. Sementes da cultivar IPR 120 foram embebidas em soluções com CM nas doses de 2,5; 5,0 e 10,0 g i.a. kg -1 de sementes por 12 horas e secas a sombra em local ventilado, e testemunha sem tratamento. A avaliação foi feita por meio dos testes de germinação após armazenamento de 0, 30, 60, 90 e 180 dias após o tratamento (DAT). Aos 60 DAT foi avaliado o comprimento de plântulas, em rolo de papel, e a altura da planta, da inserção do nó cotiledonar, da área foliar e a massa da matéria seca de folhas e caule avaliada depois de um período de 24 dias após a emergência das plântulas cultivadas em vasos. O delineamento experimental foi o inteiramente casualizado com vinte tratamentos e quatro repetições, em esquema fatorial (4 doses e 5 tempos de armazenamento), para avaliar o teste de germinação. As sementes embebidas em cloreto de mepiquat podem ser armazenadas por pelo menos 60 dias, sem redução na sua qualidade fisiológica e mantendo o efeito redutor no crescimento das plantas, apresentando crescimento menor, antes mesmo da emergência e persiste por, pelo menos, 180 dias após o tratamento. Termos para indexação:Gossypium hirsutum L., regulador de crescimento, tratamento de sementes, persistência no efeito. ABSTRACTSowing is not usually possible immediately after seed treatment. This work was aimed at determining the effect of the storage of cotton seeds soaked with mepiquat chloride (growth regulator) on physiological quality and maintenance of this effect as a plant regulator. Cotton seeds from cultivar IPR 120 were soaked in solutions with mepiquat chloride in doses of zero (control), 2,5: 5,0 and 10,0 g a.i.kg -1 of seeds for 12 hours and dried in the shade in an aerated place. The evaluation was done through germination at zero, 30, 60, 90 and 180 days after the treatment (DAT). 60 DAT the seedling length was evaluated in paper rolls. Seeds stored for 60 DAT were cultivated in pots and plant height and cotyledonary knot insertion, foliar area and dry mater of leaf and branch were appraised for a period of 24 days after emergence. The experimental design was completely randomized with twenty treatments and four replications, using a random factorial (four doses and five time of storage). There was no emergence capacity and vigor loss up to 60 DAT and the effect of the plant regulator on plant height and cotyledonary knot insertion was maintained. Seeds soaked in mepiquat chloride can be stored for at least 60 days without physiological quality reduction and maintaining the reducing agent effect on plant growth, showing lower growth, even before the emergence, lasting for at least 180 days after treatment.Index terms: Gossypium hirsutum L., growth regulator, seed treatment, persistence on the effect. INTRODUÇÃOUma...

Early development of cotton as affected by seed treatment with cyclanilide combined with mepiquat chloride

“…The combination of mepiquat chloride and cyclanilide enhanced the effects on shoot growth of cotton plants even when its respective concentration of mepiquat chloride was lower than that used for MC-alone treatment, indicating that cyclanilide synergized with mepiquat chloride. However, this synergism was observed in comparison with a single MC-rate of 4.5 g kg -1 seeds, which is low compared with MC-rates tested in previous studies (Nagashima, 2010b;Oliveira et al, 2011). It is possible that the synergism between mepiquat chloride and cyclanilide occurs only with low MC-rates.…”

“…In comparing the results of seed treatment, plant height and height of cotyledon node were decreased by plant growth regulators (Tables 1 and 2), according to results of previous experiments (Iqbal et al, 2005;Nagashima et al, 2005;Nagashima et al, 2010a;Nagashima et al, 2010b). The heightgrowth rates calculated from original height data revealed that the treatment of seeds with plant growth regulators retarded shoot growth until 31 DAE (MC and the lowest MC+CY rate) and 38 DAE (the highest MC+CY rate) compared with the control (data not shown).…”

Physical and chemical methods to breach seed dormancy of sugar apple

“…The authors reported that the best germination results were obtained when seeds were scarified with sandpaper. Nagashima et al (2010) observed that the different responses, both in seedling growth and emergence associated to the use of physical and chemical dormancy breaking methods, also depend on genetic and environmental factors.…”