Effect of heat shock on ultrastructure and calcium distribution in Lavandula pinnata L. glandular trichomes

Abstract

The effects of heat shock (HS) on the ultrastructure and calcium distribution of Lavandula pinnata secretory trichomes are examined using transmission electron microscopy and potassium antimonate precipitation. After 48-h HS at 40°C, plastids become distorted and lack stroma and osmiophilic deposits, the cristae of the mitochondria become indistinct, the endoplasmic reticulum acquires a chain-like appearance with ribosomes prominently attached to the lamellae, and the plasma and organelle membranes become distorted. Heat shock is associated with a decrease in calcium precipitates in the trichomes, while the number of precipitates increases in the mesophyll cells. Prolonged exposure to elevated calcium levels may be toxic to the mesophyll cells, while the lack of calcium in the glands cell may deprive them of the normal protective advantages of elevated calcium levels. The inequality in calcium distribution may result not only from uptake from the transpiration stream, but also from redistribution of calcium from the trichomes to the mesophyll cells.

Calcium distribution during pollen development ofUncaria hirsutaHavil. (Rubiaceae), with special reference to the function of the protruding oncus

“…Calcium precipitated by potassium antimonite is exchangeable cellular Ca 2+ that is sufficiently loosely bound to combine with antimonite (Wick & Hepler 1982), and they appear as electrondense precipitates under an electron microscope. These electron-dense precipitates are confirmed to be calcium-induced precipitates by EGTA (ethylene glycol tetraacetic acid) incubation controls and X-ray analysis Kong & Jia 2004;Huang et al 2013). The method is extensively used to indicate the relative content of calcium ion in a particular physiological period, and to detect calcium distribution in a tissue or cells site.…”

Interação cálcio e boro na fixação biológica de nitrogênio na soja: avaliação morfológica, ultraestrutural e da atividade da nitrogenase

“…As causas para que ocorram estas alterações podem ser diversas, como exemplo podemos citar os choques de temperatura (HUANG et al, 2013), bem como o estresse hídrico (ZHANG et al, 2015), salinidade (BASTÍAS et al, 2013), doenças (SUZUKI et al, 2003) e por fim, fatores relacionados a nutrição mineral de plantas Avaliando os efeitos da deficiência de B na ultraestrutura da parede celular, em dois cultivares de Brassica Napus (mais e menos tolerantes à deficiência de B), Pan et al (2012) constataram que a deficiência de B provocou alterações na estrutura da parede celular das folhas, especialmente no cultivar menos tolerante à baixas doses de B, tornando-se esta mais espessa e inchada em comparação com a parede celular das plantas cultivadas com a dose controle de B (25 µmol L -1 ). Soma-se a isso que a lamela média nas células das folhas deficientes em B apresentou ainda alterações estruturais, possivelmente devido a aberrações ocorridas durante a síntese de pectina.…”