Physiological Studies in Germination of Mangroves

Joshi, G. V.; Pimplaskar, Meera; Bhosale, Leela J.

doi:10.1515/botm.1972.15.2.91

Cited by 12 publications

(8 citation statements)

References 2 publications

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“…The embryos and viviparous seedlings of all species examined had lower internal salt concentrations than their parent shoots or leaves (Lotschert and Liemann, 1967;Joshi et al, 1972). This feature is thought to allow the maturing tissues of the embryo to reach a stage when their sensitivity to the harmful effects of salt had decreased below that of a "typical", non-viviparous embryo.…”

Section: Ecologymentioning

confidence: 99%

Salt/Water Relationships in Mangroves

et al. 1999

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Mangroves form extensive, unique communities in tropical coastal areas and tidal lowlands, dominating 60–75% of tropical shorelines. The aim of the present review is to summarize the current knowledge concerning the mechanisms underlying the most striking feature of these plants—their unique ability to obtain water from the surrounding sea. Mangroves are thought to accomplish this by rejecting potentially harmful salts. Some species actively excrete those salts leaking into the plant by means of specialized salt glands in their leaves. Mangroves are rooted in anaerobic soils, a condition giving rise to the spectacular aerial roots, such as pneumatophores and stilt roots, characteristic of mangroves, that provide oxygen to submerged tissues.We shall also discuss recent studies that have focused on physiological issues in mangroves, such as oscillatory behavior of their stomata, the structure and function of salt glands, and the compatible solutes in their leaves, which balance the osmotic pressure of the seawater. Salinity effects on their germination, distribution, CO2assimilation, respiration, and the functioning of some of their enzymes have also been examined.Finally, we shall draw attention to open questions related to the salt and water regime of mangroves and the underlying mechanisms responsible for their remarkable success in a hostile environment.

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Section: Ecologymentioning

confidence: 99%

Salt/Water Relationships in Mangroves

et al. 1999

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“…The reason for such an observation may be that in viviparous species germination and subsequent development of the propagule take place while the fruit is still attached to the mother plant (Tomlinson, 1994). Thus, the adaptation of the propagule to saline environments actually starts before dispersal (Joshi et al ., 1972) and gives an added advantage for them to establish even at high saline conditions.…”

Section: Discussionmentioning

confidence: 99%

Effect of salinity on seed germination of five mangroves from Sri Lanka: use of hydrotime modelling for mangrove germination

et al. 2018

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Mangroves are highly adapted to extreme environmental conditions that occur at the interface of salt and fresh water. Adaptations to the saline environment during germination are a key to mangrove survival, and thereby, its distribution. The main objective of this research was to study the effect of salinity on seed germination of selected mangrove species and the application of a hydrotime model to explain the relationship between water potential of the medium and rate of seed germination. Germination of seeds was examined at 15, 25 and 35°C in light/dark over a NaCl gradient. Germination time courses were prepared, and germination data were used to investigate whether these species behave according to the principles of the hydrotime model. The model was fitted for the germination of Acanthus ilicifolius seeds at 25°C. Final germination percentage was significantly influenced by species, osmotic potential and their interaction at 25°C. Moreover, temperature had a clear effect on seed germination (Sonneratia caseolaris and Pemphis acidula) which interacted with osmotic potential. Only A. ilicifolius seeds behaved according to the hydrotime principles and thus its threshold water potential was –1.8 MPa. Optimum germination rates for seeds of the other species occurred at osmotic potentials other than 0 MPa. The descending order of salinity tolerance of the tested species was Aegiceras corniculatum > Sonneratia caseolaris > Acanthus ilicifolius > Pemphis acidula > Allophylus cobbe, suggesting that the viviparous species (A. corniculatum) is highly salt tolerant compared with the non-viviparous species. The results revealed that seeds of the study species exhibited facultative halophytic behaviour in which they can germinate over a broad range of saline environments. Use of a hydrotime model for mangroves was limited as germination of their seeds did not meet model criteria.

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“…The capacity of C. tagal to invade upper estuarine habitats may thus be dependent on the tolerance shown to salt at this very early developmental stage ( Harradine, 1982 ; Krauss et al , 1998 ). Adaptation of viviparous propagules to saline environments starts when they are still attached to the mother tree, by continuously absorbing salt from the tree or by a desalinating process ( Joshi et al , 1972 ; Zheng et al , 1999 ). The tolerance of C. tagal also extended to young plants.…”

Section: Discussionmentioning

confidence: 99%