Prolina livre em alecrim-pimenta sob estresse hídrico antes da colheita

Abstract

RESUMO:O estresse hídrico é considerado um dos fatores limitantes para o desenvolvimento das plantas, com isso, os vegetais desenvolvem mecanismos para tolerar a deficiência hídrica do solo. Entre esses mecanismos, está o acúmulo de prolina livre nos tecidos, tendo como função a regulação osmótica dos tecidos. A influência do estresse hídrico em plantas medicinais ainda é pouco estudado, principalmente em plantas nativas, como é o caso do alecrim-pimenta Lippia sidoides Cham. Assim, o trabalho teve por objetivo avaliar a prolina livre e o teor de flavonoides totais na referida espécie sob condições de estresse hídrico antes da colheita. O trabalho foi realizado no Instituto de Ciências Agrárias da UFMG, Campus Montes Claros, delineamento em blocos casualizados, com 5 tratamentos e 4 repetições, sendo eles 8, 6, 4, 2 e 0 dias de supressão da irrigação antes da colheita. Os teores encontrados de prolina variaram entre 0,2489 a 3,2421 ìM.g -1 de matéria seca e de flavonoides entre 0,0139 a 0,008 g.g -1 . Os resultados observados indicam que a planta diminui seu teor de flavonoides e aumenta o teor de prolina com o aumento do período de estresse.Palavras chave: Lippia sidoides Cham., prolina, flavonoides totais, estresse hídrico. ABSTRACT: Free proline in Lippia sidoidesCham. under water stress before harvest. Water stress is considered a limiting factor for plant growth, thus, the plants develop mechanisms to tolerate the soil water deficit. Among these mechanisms is the accumulation of free proline in tissues, with the poke the osmotic regulation of tissues. The influence of water stress in medicinal plants is still poorly studied, mainly on native plants such as rosemary-pepper Lippia sidoides Cham. Thus, the study aimed to evaluate the free proline and total flavonoid content in that species under conditions of water stress before harvest. The study was conducted at the Institute of Agricultural Sciences, UFMG, Campus Montes Claros, randomized block design with 5 treatments and 4 replicates, and they 8, 6, 4, 2 and 0 days of withholding irrigation before harvest. The content of proline ranged from 0.2489 to 3.2421 ìM.g-1 of dry matter and flavonoids from 0.0139 to 0.008 gg-1. The results indicate that the plant reduces its content of flavonoids and proline content increases with increasing stress time.Key words: Lippia sidoides Cham., proline, flavonoids, water stress. INTRODUÇÃOO estresse por deficiência hídrica ocorre quando pouca água está disponível em um estado termodinâmico apropriado. Essa situação pode ocorrer por uma série de razões, tais como, excesso de evaporação, água ligada osmoticamente aos solos salinos, ou ainda, devido ao congelamento nos solos. As plantas têm mecanismos bioquímicos desenvolvidos para lidar com a falta de água, os processos desencadeados pela seca e a adaptação à alta disponibilidade de água em períodos curtos são bastante desiguais, sendo que cada célula tem mais de um mecanismo para reagir à seca, e tem por assim dizer, uma rede de segurança múltipla (Schulze et al., 2005).En...

Irrigation and organic fertilization on the production of essential oil and flavonoid in chamomile

“…There was a decrease of 25% in the content of flavonoids between the irrigation depths of 150% ETo and 0% ETo for the organic fertilization with poultry manure at the dose of 5 kg m -2 ( Figure 4A). Alvarenga et al (2011) concluded that the water deficit caused reduction of 60% in the content of flavonoids in rosemary pepper (Lippia sidoides).…”

“…There was a decrease of 25% in the content of flavonoids between the irrigation depths of 150% ETo and 0% ETo for the organic fertilization with poultry manure at the dose of 5 kg m -2 ( Figure 4A). Alvarenga et al (2011) concluded that the water deficit caused reduction of 60% in the content of flavonoids in rosemary pepper (Lippia sidoides).The irrigation depth of 150% ETo ( Figure 4A), associated with the poultry manure dose of 5 kg m -2 resulted in the highest content of essential oil, 0.36 mL 100g -1 of capitulum dry matter. The obtained content was below the minimum required by the Brazilian Pharmacopeia (ANVISA, 2010) (0.4 mL 100g -1 ) for commercialization.…”

Idioblasts formation and essential oil production in irrigated Piper aduncum

“…When subjecting the plant to stressful conditions that limit its development, the resources intended to the growth of idioblasts and the production of essential oils are channeled into other forms of adjustment and adaptation, for example, the production of free proline for osmotic cell adjustment (Bohnert et al 1995, Alvarenga et al 2011, Krishania et al 2013). Furthermore, as water availability in the soil becomes restricted, the amount of idioblasts does not imply a higher essential oil production ( Figure 2).…”

“…Nonetheless, the physiological adjustment in each setting tends to be different. As far as the idioblast production is concerned, when the plant is under moderate stress it increases, and under more severe conditions there is a channeling of the plant energy into developing other ways of adapting, like the production of free proline for osmotic cell adjustment (Bohnert et al 1995, Alvarenga et al 2011. That being the case, further research and studies regarding phenotypic plasticity and physiological responses of Piper sp.…”

Organic solutes in coconut palm seedlings under water and salt stresses

“…According to Alvarenga et al (2011), proline acts in osmotic adjustment, stabilization of subcellular structures and elimination of free radicals or, also, it can constitute a potential stock of nitrogen and carbon, which can be metabolically used after the period of exposure to the stress.…”