Gas Exchange in Different Varieties of Banana Prata in Semi-Arid Environment

Abstract

-This study aimed to evaluate gas exchange of banana prata in two production cycles in semiarid environment. Six cultivars were used as treatments arranged into a completely randomized design with five replications and four plants per plot. For physiological characteristics, it was considered a factorial arrangement of 6x14x2, six cultivars, 14 periods (months), two readings, 8h and 14h in each period. The rates of gas exchange, the carboxylation efficiency and the instantaneous efficiency of water use were higher at 8h and lower at 14h, with rare exceptions. The 'BRS platina' had a higher leaf temperature, higher transpiration and lower water use efficiency. 'Prata-Anã', 'FHIA-18' and 'Maravilha' expressed lower leaf temperature and lower transpiration. The 'Maravilha' is the most efficient in water use. Transpiration increases linearly with the leaf temperature, while the instantaneous efficiency of water use decreases linearly. Index terms: Musa spp., AAB and AAAB, physiological variables. TROCAS GASOSAS EM DIFERENTES CULTIVARES DE BANANEIRAS TIPO PRATA EM AMBIENTE SEMIÁRIDORESUMO -Objetivou-se com o presente trabalho avaliar as trocas gasosas de bananeiras tipo prata, em dois ciclos de produção em ambiente semiárido. Utilizaram-se seis cultivares como tratamentos dispostos em um delineamento experimental inteiramente casualizado, com cinco repetições e quatro plantas úteis por parcela. Para as características fisiológicas, considerou-se um arranjo em esquema fatorial 6x14x2, seis cultivares, 14 épocas de avaliação (meses) e dois horários de leitura (8h e 14h), em cada época. As taxas de trocas gasosas, a eficiência de carboxilação e a eficiência instantânea do uso da água foram maiores às 8h e menores às 14h, com raras exceções. A 'BRS platina' apresentou maior temperatura foliar, maior transpiração e menor eficiência de uso da água. 'Prata-Anã', 'FHIA-18' e 'Maravilha' expressaram menor temperatura foliar e menor transpiração. A 'Maravilha' é mais eficiente no uso da água. A transpiração aumenta de maneira linear com o aumento da temperatura foliar, enquanto a eficiência instantânea do uso da água decresce linearmente. Termos para indexação: Musa spp., AAB e AAAB, variáveis fisiológicas.

Growth, yield and gas exchanges of ‘D’Angola’ plantain under different plant densities

“…The photosynthesis was higher at 8:00 h, and transpiration was higher at 14:00 h (Table 3), as also found by Arantes et al (2016) for banana. The increase in temperature combined with a low air relative humidity -a high atmosphere vapor pressure deficit, which is common for the local semiarid conditions, mainly in September, October and February (Donato et al, 2015) -increases the evapotranspiration demand and affects all metabolic and physiological processes of the plant.…”

Precocity, yield and water-use efficiency of banana plants under planting densities and irrigation depths, in semiarid region

“…These values, normally observed for Prata-type banana plants in the first cycle, are similar to those of Marques et al (2018), in which 21.31 t ha -1 of hands were recorded from a population of 2,000 plants ha -1 . Conversely, Donato et al (2015b) reported that well-managed banana plantations under better conditions of climate, such as maximum temperatures below 34 ºC, less windrelated damage and higher relative humidity, i.e., favoring a higher carboxylation and instantaneous water-use efficiency (Donato et al 2015a, Arantes et al 2016, Ramos et al 2018, may yield more than 40 t ha -1 cycle -1 (high yield > 32 t ha -1 cycle -1 ), particularly from the second production cycle on. The lack of irrigation depth effect on the yield of the first production cycle was also observed by Santos et al (2016), who, by studying Prata-Anã and BRS Platina, did not verify differences in yield between the two cultivars or lack of effects for lowering the irrigation depth, although the yield recorded herein (20.25 t ha -1 ) was higher than that found by Santos et al (2016) (9.59 t ha -1 ).…”

“…The higher leaf temperature increased the transpiration and reduced the instant water-use efficiency (Santos et al 2017). On the other hand, temperatures close to the optimal one for photosynthesis in banana plants (27 ºC) (Donato et al 2015c) contribute to the increase in the carboxylation efficiency of rubisco (Arantes et al 2016, Ramos et al 2018) and water-use efficiency (Arantes et al 2018), leading to higher net photosynthesis and yields, what ensures the application of lower irrigation depths. In this study, temperatures close to optimal occurred in midyear months, while temperatures hindering photosynthesis (higher than 34 ºC) were recorded mainly in September, October, February and March.…”

Physiological behavior of melon cultivars submitted to soil salinity1

“…Regarding the cultivars, regardless of saline concentrations, it was verified that the net CO 2 assimilation was higher in the Iracema cultivar (6.75 dS m -1 ), surpassing in 4.74 % and 4.59 % the Goldex and Natal cultivars, respectively (Table 4). The difference in the physiological behavior among cultivars is due to a genotype variation, in response to the environment, being possible to select cultivars superior to others (Arantes et al 2016).…”