The influence of variations in irradiance upon morphology in an unattached form of Gracilaria gracilis (Stackhouse) Steentoft during field cultivation, South Primorye, Russia
Skriptsova, A.V.; Yakovleva, I.M. (2002). The influence of variations in irradiance upon morphology in an unattached form of Gracilaria gracilis (Stackhouse) Steentoft during field cultivation, South Primorye, Russia. Aquat. Ecol. 36(4): 511-518
In: Aquatic Ecology. Springer: Dordrecht; London; Boston. ISSN 1386-2588; e-ISSN 1573-5125, more
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| Authors | | Top |
- Skriptsova, A.V.
- Yakovleva, I.M., correspondent
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| Abstract |
The changes in morphology and anatomy of an unattached form of Gracilaria gracilis from Southern Primorye, Russia, were investigated as a response to different photon irradiances. Plants were grown at 5, 10, 60 and 95% of the incident PAR in the field from mid July to mid September, and a quantitative evaluation of various morphological characteristics was made: thickness and length of branches, thickness of the cuticle and cell walls, cell length and diameter, the ratios between the area of photosynthetic and structural tissue. All characteristics showed variations that could be attributed to irradiance. The narrow light range of 60-95% PAR was the growth optimum for Gracilaria gracilis. At these irradiances, the biomass increase was related to the growth of the branches in length (r = 0.95, P < 0.05) and thickness (r = 0.99, P < 0.05), and increased branch density. Growth of the branches only in length, the formation of the thin cortical cell walls and cuticle, and increased ratios of photosynthetic to structural tissues were among the effects of low irradiances (5-10% PAR) on plant morphology. The relationship of morphology and productivity factors to irradiance intensity provide evidence for their environmental rather than genetic control. Differences in thallus morphology and anatomy together with variations in levels of photosynthetic pigments are discussed in terms of the adaptive strategies of unattached Gracilaria gracilis to light fluctuations. |
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