Plant regulators and invertase activity in sugarcane at the beginning of the harvest season / Reguladores vegetais e atividade de invertases em cana de açúcar no início da safra

Invertases play an essential role in partitioning photosynthates between storage and growth. The objective of this study was to evaluate the activity of acid and neutral invertases and the role they play in controlling the accumulation of sucrose in sugarcane as a result of the application of plant regulators in the beginning of the cropping season.A randomized block experimental design was adopted, with five replicates.The treatments consisted in the application of three plant regulators of the class of growth inhibitors (Sulfomethuron-methyl - 20g ha-1, Glyphosate - 0.4L ha-1, and Compounds from organic carboxylic radicals + Glyphosate - 1L ha-1 + 0.15L ha-1), in addition to a control (natural ripening).The acid and neutral invertase levels are affected in different ways and intensities, due to the active principle used as ripening agent and to the weather conditions.In sugarcane variety RB85-5453, with the conditions described in this experiment, it is suggested high levels of soluble acid invertase in relation to levels of neutral invertase; however, the first was characterized by high sucrose content in the stalks.Inverse correlation could be established for sugarcane variety RB85-5453 between soluble acid invertase levels and effective sucrose accumulation in the stalks.

Invertases desempenham um papel essencial no particionamento de fotossintatos entre armazenamento e crescimento. O objetivo deste estudo foi avaliar a atividade das enzimas invertases ácida e alcalina (neutra) e o papel que desempenham no controle do acúmulo de sacarose em cana-de-açúcar, como resultado da aplicação de reguladores vegetais no início da época de colheita. O delineamento experimental utilizado foi em blocos ao acaso, com cinco repetições. Os tratamentos consistiram na aplicação de três reguladores vegetais da classe dos inibidores de crescimento (Sulfometuron-metil - 20g ha-1, Glifosato - 0,4L ha-1, e Compostos de radicais carboxílicos orgânicos + Glifosato - 1L ha-1 + 0,15L ha-1), além do controle (maturação natural). Os níveis das invertases ácida e neutra são afetados de maneiras e intensidades distintas, devido ao princípio ativo utilizado como agente de maturação e das condições meteorológicas. Para a variedade RB85-5453, nas condições descritas neste experimento, sugerem-se níveis elevados de SAI em relação à NI;no entanto, a primeira foi caracterizada por um elevado teor de sacarose nos colmos. Correlação inversa pode ser estabelecida entre a atividade da invertase ácida e o acúmulo de sacarose.

Plant regulators and invertase activity in sugarcane at the beginning of the harvest season / Reguladores vegetais e atividade de invertases em cana de açúcar no início da safra

Invertases play an essential role in partitioning photosynthates between storage and growth. The objective of this study was to evaluate the activity of acid and neutral invertases and the role they play in controlling the accumulation of sucrose in sugarcane as a result of the application of plant regulators in the beginning of the cropping season.A randomized block experimental design was adopted, with five replicates.The treatments consisted in the application of three plant regulators of the class of growth inhibitors (Sulfomethuron-methyl - 20g ha-1, Glyphosate - 0.4L ha-1, and Compounds from organic carboxylic radicals + Glyphosate - 1L ha-1 + 0.15L ha-1), in addition to a control (natural ripening).The acid and neutral invertase levels are affected in different ways and intensities, due to the active principle used as ripening agent and to the weather conditions.In sugarcane variety RB85-5453, with the conditions described in this experiment, it is suggested high levels of soluble acid invertase in relation to levels of neutral invertase; however, the first was characterized by high sucrose content in the stalks.Inverse correlation could be established for sugarcane variety RB85-5453 between soluble acid invertase levels and effective sucrose accumulation in the stalks.(AU)

Invertases desempenham um papel essencial no particionamento de fotossintatos entre armazenamento e crescimento. O objetivo deste estudo foi avaliar a atividade das enzimas invertases ácida e alcalina (neutra) e o papel que desempenham no controle do acúmulo de sacarose em cana-de-açúcar, como resultado da aplicação de reguladores vegetais no início da época de colheita. O delineamento experimental utilizado foi em blocos ao acaso, com cinco repetições. Os tratamentos consistiram na aplicação de três reguladores vegetais da classe dos inibidores de crescimento (Sulfometuron-metil - 20g ha-1, Glifosato - 0,4L ha-1, e Compostos de radicais carboxílicos orgânicos + Glifosato - 1L ha-1 + 0,15L ha-1), além do controle (maturação natural). Os níveis das invertases ácida e neutra são afetados de maneiras e intensidades distintas, devido ao princípio ativo utilizado como agente de maturação e das condições meteorológicas. Para a variedade RB85-5453, nas condições descritas neste experimento, sugerem-se níveis elevados de SAI em relação à NI;no entanto, a primeira foi caracterizada por um elevado teor de sacarose nos colmos. Correlação inversa pode ser estabelecida entre a atividade da invertase ácida e o acúmulo de sacarose.(AU)

HbNIN2, a cytosolic alkaline/neutral-invertase, is responsible for sucrose catabolism in rubber-producing laticifers of Hevea brasiliensis (para rubber tree).

In Hevea brasiliensis, an alkaline/neutral invertase (A/N-Inv) is responsible for sucrose catabolism in latex (essentially the cytoplasm of rubber-producing laticifers, the source of natural rubber) and implicated in rubber yield. However, neither the gene encoding this enzyme nor its molecular and biochemical properties have been well documented. Three Hevea A/N-Inv genes, namely HbNIN1, 2 and 3, were first cloned and characterized in planta and in Escherichia coli. Cellular localizations of HbNIN2 mRNA and protein were probed. From latex, active A/N-Inv proteins were purified, identified, and explored for enzymatic properties. HbNIN2 was identified as the major A/N-Inv gene functioning in latex based on its functionality in E. coli, its latex-predominant expression, the conspicuous localization of its mRNA and protein in the laticifers, and its expressional correlation with rubber yield. An active A/N-Inv protein was partially purified from latex, and determined as HbNIN2. The enhancement of HbNIN2 enzymatic activity by pyridoxal is peculiar to A/N-Invs in other plants. We conclude that HbNIN2, a cytosolic A/N-Inv, is responsible for sucrose catabolism in rubber laticifers. The results contribute to the studies of sucrose catabolism in plants as a whole and natural rubber synthesis in particular.