Effects of salinity on the growth rate, carrageenan yield, and cellular structure of Kappaphycus alvarezii (Rhodophyta, Gigartinales) cultured in vitro

Abstract

Kappaphycus alvarezii was cultured in vitro under salinities ranging from 15 to 55 psu for 35 days to determine the differential effect on growth rate, carrageenan yield, and cellular structure. Plants kept in 15 psu died after 3 days, while plants cultured in 55 psu presented low growth rates during the entire experimental period (0.28% day −1 ). Plants cultured in 25, 35, and 45 psu showed growth rates normally associated with this species (between 3% and 4% day −1 ) and similar cellular morphology. Carrageenan yield was significantly higher in plants cultured in 25 psu in relation to the other treatments. As observed by light microscopy, plants cultured in 15 psu showed cellular turgidity and increased cell wall thickness, both consequences of hyposalinity. Chloroplasts and other membranous organelles underwent rupture and considerable disorganization in ultrastructure. Although branches from the 55 psu samples showed plasmolysis, cells were able to maintain chloroplast integrity, despite their rudimentary features. In high salinities, great concentrations of floridean starch grains were observed in subcortical cells, indicating their probable participation in osmoregulation. Based on these results, we defined the range of 25 to 45 psu as the limits of saline tolerance for K. alvarezii. While new field studies are required to confirm these results, it can be concluded that new sites, such as inactive or abandoned shrimp tanks with salinities up to 25 psu, could be considered for commercial farming.

Changes of photosynthetic performances in mature thalli of the red alga Gelidium amansii (Gelidiaceae) exposed to different salinities

“…This phenomenon suggests that G. amansii is very sensitive to higher salinity, and that 35 psu might be an upper limit for plant growth, which is lower than for other red algae, e.g. Gracilaria corticata (40 psu) (Kumar et al 2010) and Kappaphycus alvarezii (45 psu) (Hayashi et al 2011).…”

“…Gracilaria corticata (J. Agardh) J. Agardh exposed to 15 psu showed lowered thallus rigidity after 9 days of exposure (Kumar et al 2010). Also, Hayashi et al (2011) recorded the disorganization of the cell ultrastructure and the disruption of turgid chloroplast cells in the cortical and subcortical cells of Kappaphycus alvarezii (Doty) Doty ex P.C. Silva cultured at 15 psu.…”

“…Similarly, salinity stress may occur for submerged algae in estuarine conditions, where tidal flows may cause large changes in salinity. Previous studies suggested that salinity played an important role in the upper distribution limit and artificial cultivation yield of seaweeds (Stepanian 2009;Hayashi et al 2011). The tolerance strategies of halophytes living at high salinities, e.g.…”

Iptek bagi Masyarakat Kelompok Pembudidaya Rumput Laut di Desa Labuhan Sangoro yang Mengalami Kendala Ketersediaan Bibit

“…Effendi (2003) yang menyatakan bahwa kisaran salinitas perairan laut berkisar antara 3040 psu. Pertumbuhan dan kandungan beberapa spsesies rumput laut seperti Kappapycus alvarezii dan Gracilaria verucosa sangat dipengaruhi oleh salinitas tempat hidup (Jansi  Ramdhas 2009;Choi et al 2010;Hayashi et al 2011). Selain aspek ekologi dan sosial ekonomi (ketersediaan tenaga kerja dan keuntungan ekonomi), aspek risiko juga dipertimbangkan dalam pemilihan lokasi ini.…”

Fenologia, aspectos ecofisiológicos e seleção de linhagens em cultivos no mar de Gracilaria birdiae (Rhodophyta, Gracilariales) no Estado do Rio Grande do Norte, Brasil

“…Com relação ao sul e sudeste do país, estudos com Kappaphycus alvarezii foram conduzidos no estado de São Paulo (PAULA et al, 1999HAYASHI et al, 2007a, b) e outros estão em andamento em Santa Catarina (HAYASHI et al, 2011). Atualmente, são encontrados cultivos comerciais dessa espécie no estado do Rio de janeiro, nas baías de Ilha Grande e de Sepetiba (REIS et al, 2005;CASTELAR et al, 2009a, b).…”