Efeito da densidade de semeadura e de reguladores vegetais sobre os caracteres morfofisiológicos da folha bandeira do trigo

Abstract

Efeito da densidade de semeadura e de reguladores vegetais sobre os caracteres morfofisiológicos da folha bandeira do trigo RESUMO O presente trabalho teve por objetivo estudar as características morfofisiológicas da folha bandeira do trigo em densidades crescentes de semeadura sob aplicação de reguladores vegetais. O delineamento experimental utilizado foi o de blocos casualizados em esquema de parcelas subdivididas com quatro repetições. As parcelas foram constituídas por quatro densidades de semeadura (30, 50, 70 e 90 plantas m -1 ), enquanto as subparcelas foram constituídas pela aplicação de reguladores vegetais, sendo um produto comercial composto por auxina+giberelina+citocinina (Ax+GA+CK), Etil-Trinexapac e a combinação dos dois produtos, além de uma testemunha sem a aplicação. Foram determinados o acúmulo de matéria seca total e a altura de plantas, as características morfológicas, o índice SPAD e os teores de nitrogênio e pigmentos fotossintéticos da folha bandeira. O aumento da densidade de semeadura resultou em diminuição no acúmulo de matéria seca e no índice SPAD da folha bandeira. A aplicação de Etil-Trinexapac resultou em aumento no índice SPAD da folha bandeira, estando os valores mais correlacionados com os teores de nitrogênio foliar do que com os teores de clorofila, que apresentaram redução em função da aplicação do regulador. A aplicação de Ax+GA+CK não afetou o desenvolvimento da folha bandeira de plantas de trigo. Palavras-chave:Auxina, citocinina, clorofila, Etil-Trinexapac, giberelina, nitrogênio, SPAD. Effects of sowing density and plant growth regulators on the morphological and physiological characteristics of the wheat flag leaf ABSTRACTThe objective of this work was to study the morphological and physiological characteristics of the wheat flag leaf as affected by increasing sowing densities and plant growth regulators application. The experimental design was a split-plot with completely randomized blocks and four replications. Plots were consisted by four sowing densities (30, 50 70 and 90 plants m -1 ) and the split-plots by plant growth regulators: a product composed by auxin+gebberellin+cytokinin (Ax+GA+CK), Trinexapac-Ethyl e (Ax+GA+CK) + Trinexapac-Ethyl, and a control without application. Dry mass accumulation, plant height, morphological characteristics, SPAD index, nitrogen and photosynthetic pigments contents in the flag leaf were determined. The increase in the sowing density resulted in lower dry mass accumulation and SPAD index of the flag leaves. Trinexapac-Ethyl caused increase in the SPAD index, but the chlorophyll content of the flag leaf was reduced. The SPAD index values were more correlated with the nitrogen than the chlorophyll contents. Ax+GA+CK did not affect flag leaf characteristics in wheat plants.

Physiological aspects in cotton cultivars in response to application leaf gibberellic acid

“…BRS Safira, not set to no regression model with increased doses and GA 3, was represented by the average value of 6.32. Unlike the results observed in this study, Fioreze and Rodrigues (2012) evaluating the effect of applying foliar biostimulant auxin base + gibberellin + cytokinin in wheat plants (Triticum spp. ), found no response in chlorophyll a/b flag leaf.…”

Effect of salicylic acid in two stages of application on wheat crop

“…Among the physiological and biochemical transformations in plants in response to SA application, increases in chlorophyll levels are cited (Kalaki et al, 2014). According to Fioreze & Rodrigues (2012) there is a positive correlation between plant regulators and the SPAD index. In flowers of carnation (Dianthus caryophyllus L. cv.…”

Agronomic performance of wheat genotypes and the use of nitrogen doses

“…The cultivar TBIO Noble expressed the highest average of ear grain weight (Table 3). The ability to maintain productive tillers is associated with the supply of N to the plant, and this character contributes to an increase in the number of fertile ears, especially at low sowing densities (Fioreze & Rodrigues, 2012;Fioreze & Rodrigues, 2014;Ferrari et al, 2016). Therefore, the TBIO Ponteiro cultivar had the highest average number of tillers, while the lowest average was for the ORS 1403 cultivar.…”

“…However, the chosen sowing density is also of great importance, and therefore it is one of the key points for the highest grain yield, and along with it comes the fertilization management. Because it is a crop that allows for different management situations, presenting a relatively constant productive behavior (Fioreze & Rodrigues, 2012;Fioreze & Rodrigues, 2014). Thus, this work aimed to evaluate the agronomic performance of wheat cultivars and to evaluate the use of nitrogen doses.…”