Ananas comosus (L.) Merr. var. Smooth Cayenne plants when grown in vitro under different temperature regimes developed as CAM or as C3 plants. The plants used in this study were developed from the lateral buds of the nodal etiolated stem explants cultured on Murashige and Skoog medium for 3 mo. The cultures were maintained under a 16-h photoperiod for different thermoperiods. With 28°C light/15°C dark thermoperiod, as compared with constant 28°C light and dark, pineapple plants had a succulence index two times greater, and also a greater nocturnal titratable acidity and phosphoenolpyruvate carboxylase (PEPCase) activity, indicating CAM-type photosynthesis. The highest abscisic acid (ABA) level occurred during the light period, 8 h prior to maximum PEPCase activity, while the indole-3-acetic acid (IAA) peak was found during the dark period, coinciding with the time of highest PEPCase activity. These plants were also smaller with thicker leaves and fewer roots, but had greater dry weight. Their leaves showed histological characteristics of CAM plants, such as the presence of greater quantities of chlorenchyma and hypoderm. In addition, their vascular system was more conspicuous. In contrast, under constant temperature (28°C light/dark) plants showed little succulence in the leaves. There was no significant acid oscillation and diurnal variation in PEPCase activity in these plants, suggesting the occurrence of C3 photosynthesis. Also, no diurnal variation in ABA and IAA contents was observed. The results of this study clearly indicate a role for temperature in determining the type of carbon fixation pathway in in vitro grown pineapple. Evidence that ABA and IAA participate in CAM signaling is provided.
How to translate text using browser tools
1 November 2005
TEMPERATURE DETERMINES THE OCCURRENCE OF CAM OR C3 PHOTOSYNTHESIS IN PINEAPPLE PLANTLETS GROWN IN VITRO
C. C. NIEVOLA,
J. E. KRAUS,
L. FRESCHI,
B. M. SOUZA,
H. MERCIER
ACCESS THE FULL ARTICLE
It is not available for individual sale.
This article is only available to subscribers.
It is not available for individual sale.
It is not available for individual sale.
In Vitro Cellular and Developmental Biology - Plant
Vol. 41 • No. 6
November 2005
Vol. 41 • No. 6
November 2005
Abscisic acid
Ananas comosus
Auxin
Bromeliaceae
leaf histology
phosphoenolpyruvate carboxylase
thermoperiod