ISHS Acta Horticulturae 438: III International Congress on Cactus Pear and Cochineal
CHANGES IN CAM ACTIVITY ABA, AND PAS IN OPUNTIA FICUS-INDICA AS RESPONSE TO DROUGTH. |
| Authors: | G. Nieddu, I. Chessa, P. Deidda, Z. Tekle |
| Keywords: | Cactus pear, water stress |
| Abstract:
The biochemical characteristic of adaptation to drought in Opuntia ficus-indica has been investigated in the present study. The research was conducted on young self-rooted plants of cactus pear cv “Gialla”, irrigated or droughted from May 1993 to May 1994. Cladode size, fresh and dry weight, osmotic pressure, pH and titratable acidity, polyamines (PAS), and abscissic acid (ABA) levels were recorded in tissues sampled in February and in May 1994, at different hours of the day. All the plants survived after a prolonged water stress, but drought affected cladode morphology and the new cladode production. Typical day-night fluctuation in tissue pH and titratable acidity was observed in irrigated and water stressed plants both in winter (February) and in the growth season (May), but CAM activity decreased as the stress proceeded. ABA content increased as the season advanced and the highest levels of this hormone were observed in the droughted plants. Pas levels were higher in irrigated plants and increased during night, together with the greatest accumulation of malic acid. Among Pas putrescine was the main represented polyamine, followed by spermidine and spermine. Only these two polyamines increased their concentrations in water stressed plant tissues. | |
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