Effect of thermal stress on the liberation of tetraspores from Gelidium pusillum (Stackhouse) LeJolis, PterocladiLl heteroplatos

(Boergesen) Umamaheswara Rao and Kaliaperurna.l and Gelidiopsis variabilis( Greville) Schmitz was studied.

in response to temperatures lower (0° -lOOC)and higher( 40° -45°C)than the tolerance limits of plants. Spore liberation was

seen in these algae exposed to low and high temperatures for short durations but the output decreased with increase in the

duration of treatment. The temperature tolerance capacity varied in the algae tested

Kaliaperumal, N

Rao, M Umamaheswara

201-202Effect of thermal stress on the liberation of tetraspores from Gelidium pusillum (Stackhouse) Le Jolis, Pterocladia heteroplatos (Boergesen) Umamaheswara Rao and Kaliaperumal and Gelidiopsis variabilis (Greville) Schmitz was studied, in response to temperatures lower (0ᵒ -10ᵒC) and higher (40ᵒ -45ᵒC) than the tolerance limits of plants. Spore liberation was seen in these algae exposed to low and high temperatures for short durations but the output decreased with increase in the duration of treatment. The temperature tolerance capacity varied in the algae tested

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Effect of thermal stress on spore shedding in some red algae of Visakhapatnam Coast

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.-Indian Journal of Marine Sciences Vol.16,September 1987, pp. 201-202 Effect of Thermal Stress on Spore Shedding in Some Red Algae of Visakhapatnam Coast N KAUAPERUMAL' & M UMAMAHESWARA RAO Department of Botany, Andhra University. Waltair 530 003,lndia Received 3 March 1986; revised received 1 May 1987 Effect Qfthermal stress on the liberation of tetraspores from Gelidium pusillum (Stackhouse) LeJolis, PterocladiLl he-teroplatos (Boergesen) Umamaheswara Rao and Kaliaperurna.l and Gelidiopsis variabilis( Greville ) Schmitz was studied. in response to temperatures lower (0° -lOOC)and higher( 40° -45°C)than the tolerance limits of plants. Spore liberation was seen in these algae exposed to low and high temperatures for short durations but the output decreased with increase in the duration of treatment. The temperature tolerance capacity varied in the algae tested. In Gracilaria, Hypnea, Gelidium, PterocladilI and other red algae of the Visakhapatnam coast, spore dis-charge was seen at certain temperatures and tempera-ture tolerance ranges for spore shedding varied in these algae! ·2. In the present investigation experi-ments were conducted on some species of red algae to understand the effect of thermal stress on spore shedding at temperatures higher and lower than the tolerance limits of these algae. Tetrasporophytes of G. pusillum (Stackhouse) Le Jolis, P. heteroplatos (Boergesen) Umamaheswara Rao and Kaliaperumal and G. varilIbilis (Greville) Schmitz coUected from the infralittoral fringe zone at Visakhapatnam during different months in 1978, were used in the present' study. Fertile clumps of G. pusillumand P. heteroplatosand stichidia of G. varia-bilis were placed in petridishes filled with sterile seawater. Temperature treatment was given to plants kept in petridishes for 1 to 24 h and at high tempera-ture exposures of < 1 h were also used. Plants ofG. pusillum were exposed to 0', 10' and 40'C, P. hetera-. platosto 0' and 45'C and G. varilIbilisto 0', 15', 20' and 40'C. Dark incubator was used for exposing petri dishes with fruiting material at 40' and45'C and deep freezer and low temperature chamber were used for experiments at low temperatures. After treatment, experimental sets were main-tained at room temperature in a dark'Chamber for the remaining period of the day. Untreated sets kept for 24 h at room temperature were treated as controls. AI the end of each experiment the liberated spores and seawater in petri plates were mixed with a brush and • Present address: Regional Centre of Central Marine Fisheries Research Institute, Mandapam Camp 623 520, India the spores present in the seawater were counted2 us-ing a plankton counting chamber. From the mean va-lues of 2 counts and the number of sori present on the fertile clumps of G. pusillum and P. heteroplatos and stichidia of G. varilIbilis, the quantity of spores (tetra-spores per sorus or stichidium per day ) liberated were estimated. \\%Ie estimating the tetraspore output, percentage frequency of the dividing spores was cal-culated separately to know the rate of germination of spores within 24 h. Ten replicates were maintained for experiments with G. pusillum and P. heteroplatos and only 5 with G. varilIbilis. In G. pusillum the spore shedding(Fig. 1) was more than the control in fronds treated for 1 h at O'C and less than the control in fronds exposed for 2 h; shedd-ingwas inhibited completely in fronds treated for 6 h. N. 10' and 40' C the spore output decreased with in-creasing duration of exposure but at these tempera-tures some shedding was seen even after 16 h treat-ment. In P. heteroplatos rapid decline in spore output was observed (Fig. l )in plants exposed for 4 to 12hatO'C and shedding was minimum for 12 h (Fig. 1 ). N. 45'C spore output decreased within 2 h of exposure and the output was minimum between 2 and 6 h treatment at this high temperature. In G. WlrilIbilis also spore output was less than the control in treatments given at 0', 15' and 40'C (Fig. 1). Spore liberation found for I h at 40'C, for 2 hat O'C and 12 h at 15'C indicates the sensitive nature of this alga to low and high temperatures. G. varilIbilis ex-posed for 8 h at 20'C liberated ,more number of spores than the control and plants exposed for 4 h.Af-ter 8 h treatment, spore production decreased gradu-ally and shedding was seen up to 20 h treatment. 201 INDIAN J MAR SCI, VOL. 16, SEPTEMBER 1987 ,"0 4 0 30 20 _ '0 ., . ~ '- -g'2 :; OXIO ~ .6 t- -=. 12 9 • , GEUOIUM PUSILLUM 0------4 ot O----O IO"t; ............... 40·C PTEROCLA~ HETEROPLA"OS ~ o'\"; O----« <5~ 2'~----~~~~~~~~~==~-' )( 10 GEUDIOPSIS VARIABILIS 24 • ..... J r · o '~ I I!-~ 2 4 • Time (hour) ....--... o·c 0- - - -0 I~ ·C 6-----020"c ~40·C ,. 24 Fig. 1 - Variations in tetraspore output from fronds of red algae in response to temperature treatments (Vertica11ines show standard error to the mean values) Spore germination with in 24 h of experiment is giv-enin Table 1. Majority of spores liberated germinated usually from 2nd or 3rd d onwards under laboratory conditions. Therefore the rate of germination (in 24 h) was low in the present study. In G. pusillum exposed to lO'C 1-2% of spores divided and < 1 % spores of G. pusillum and P. heteroplatos germinated at 0' and 40'C treatments. Spores of G. variilf>ilis did not ger-minate in all temperatures tested (Fig. 1). Cultures and fertile thalii were exposed by some workers to a wide range of temperatures to know the relationship between temperature and sporulation . and the optimal conditions required for spore shedd-ing' -6. These experiments were conducted under constant temperature condition and studies relating to the effects of change of water temperature or ther-mal shock on spore liberation were very few 7• The present study indicates that G. pusillum, P. heteropla-lOS and G. variabilis growing at Visakhapatnam coast can tolerate exposure to very low (0' to 1 O'C) and high (40' to 45°C) temperatures and liberate spores con-202 Table 1 - Germination Rates of Tetraspores in Different Temperature Treatments Temp. Alga Duration of % germinatic:;m (0C) o 10 40 o 45 o 15 20 40 G. pusillum -do--do· P. heteroplatos -d<>-G. variabilis -do--do--do-Nc.germination thermal of tetraspores stress(h) 1-3 4-8 1/2-8 . 4 1/2-6 1/2-2 4-12 4-20 114-1 0.6-0.9 J:Z-2 .2 0.1-0.7 0.2 trary to earlier findings 7 in Gloiopeltis spp. Germina-tion was also observed especially at the low tempera-. ture tested (Table 1). However, the thermal shock giv-en could not enhance spore liberation from these al-gae. The spore output declined rapidly with increas-ing duration of treatment except in G. pusilluin treat-ed for 1 h at O'C and G. variabilis exposed for 8 h at 20°C (Fig. 1). As already suggested2 the sensitive na-ture of G. variabilis to low temperature treatments (00-10'C)- and absence of germination at different temperatures tested in this study, show that it is a sten-othermal species. liberation of spores in G. pusillum and P. heteroplalos in 5-20 h treatments at 0' and IO' C and germination of a small percentage of tetra-spores observed in this study also indicate that these Gelidioid members are eurhythermal in nature. These differences under thermal stress can be related to the geographical distribution of these red algae". The authors thank Head of the Oepartmentfor faci-lities. One of the authors (N K ) is grateful to Dr V A Parasuraman for help and to the CSIR, New Oelhi for the award of Senior Research FeUawship. References Umamaheswara Rao M"& Subbarangaiah G , Proc Symp Coastal Aquaculture (Mar Bioi A<;soc India, Cochin) (in press), 2 Umamaheswara Rao M & Kaliaperumal N, J Exp Mar Bioi EcoL,70 (1983 )45 . 3 Katada M, J Shimonoseki Coli Fish, 5 (1955) 1. 4 Kurogi M & Al9)'OJl1a K , Bull Tohoku Reg Fish Res Ldb, 26 (t 966 ) 77. 5 Kurogi M, Sato S & Yoshida T, Bull Tohoku Reg Fish Res Lab, 27 (1967 ) 131. 6 Dring M J , Algal physiology and biochentislry(Blackwell Sci Publ, London) 1974, p 814. 7 Matsui T, J Sh;monoseki Uni Fish, 17 (1969) 185. 8 Sreenivasa Rao P, Phykos, 9 (1970)63. 

Effect of thermal stress on spore shedding in some red algae of Visakhapatnam coast

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Effect of thermal stress on spore shedding in some red algae of Visakhapatnam coast

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