deleterious effects of chemical mutagens on economically important

Journal of Environmental Research And Development Vol. 2 No. 4, April-June 2008

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DELETERIOUS EFFECTS OF CHEMICAL MUTAGENS ONECONOMICALLY IMPORTANT PLANT

Hibiscus sabdariffa VAR. AMV1 LINN.

Padma Shrivastava* and H. N. Tiwari

Department of of Botany, Govt. PG College, BHEL, BHOPAL (INDIA)

Received October 13,, 2007 Accepted March 18, 2008

ABSTRACTIn the present study the chemical mutagens used were ethyl methane sulphonate, N-

methyl-N-nitro-N-nitrosoguanidine, di-ethyl sulphate and a physical mutagen representedby gamma radiation. The dry seeds were used for gamma irradiations while dry as well as 6,12 and 18 hrs. Pre-soaked seeds were utilized for chemical mutagen treatments. The differentmutagens utilized in various induced mutability of physical and chemical mutagens are alsodiscussed.

The results obtained in the present investigation are presented under the two majorheads M1 and M2 generations. In the first part, the immediate effect of all the mutagens onM1 parameters like germination, seeding height, and survival of plants, chromosomalaberrations, chlorophyll chimeras, pollen sterility and seed set are incorporated.

All these chemical mutagens induced more pollen sterility and seed sterility ineconomically important plant H. sabdariffa L. var. AMVl.

Mutagen induced genetic changes are shown in the form of pollen sterility in M1generation. Forese – Gartzen et. al., Sato and Gaul in barley, Yamaguchi in rice, Monti inNicotiana and Cornu and Dommergues in Petunia have discussed the effect of differentmutagens on this parameter. Present study indicates increase in pollen sterility withenhancement in the dose of the mutagen. The higher percentage of pollen sterility wasinduced by NMG and gamma radiations as compared to EMS and dES. Higher doses ofEMS induced 4.1 to 27.8 % and NMG induced 50.9% and 36.7% pollen sterility in dry and 6hr pre-soaked seed treatments respectively. Gaul classified the pollen sterility induced byEMS into three categories—(i) Chromosomal, (2) Genetic, and (3) Purely Physiological.

Present study also indicates the reduction in the seed set per capsule due to mutagenictreatments. In control it was 25.6 seeds per capsule. It decreased with increase in theconcentration of the mutagens.

Similar results were obtained by Muller, in Arabidopsis, Kawi and Sato in Rice andGregory in pea. In the present study EMS, dES, NMG and gamma radiations effected seedset considerably. It decreases up to 25.6 seeds to 2.2 seeds. The results clearly indicatedthat the seed sterility as a function of the dose of mutagen. Gaul argued that origin of EMSinduced sterility could be gene mutations or invisible deficiencies. Nerker observed thathigh frequency of translocations in Lathyrus is due to gamma rays and these might berelated with sterility. The occurrence of various floral variations may be related to somephysiological injury or chromosomal aberrations.

*Author for correspondence

Journal of Environmental Research And Development Vol. 2 No. 4, April-June, 2008

634

INTRODUCTIONThe general mutations concept is very

heterogeneous ranging from point mutations topolyploidy. The mutagens can act either directlyon the gene or indirectly by inhibiting antimutagens in the cells and thus interfering withthe antimutagen balance. The hydrogenperoxide-catalase-potassium-cyanide systemmay be cited as an example of this type ofinteraction, H2O2 is mutagenic. Catalase is anantimutagen, which destroy the mutageniceffect of H2O2. If catalase is inhibited by KCN,the mutation rate is enhanced, not becauseKCN is mutagenic but because the H2O2 conc.in the cells is increased1,2.

Efficient mutagenesis is the induction ofdesirable changes (mutations) free from theusually associated undesirable effects likegrowth inhibition, lethality, sterility andchromosomal aberrations. Mutagenic efficiencyof a treatment induced to the accompanyingundesirable effects3.

Hibiscus sabdariffa var. AMV1 is afibrous plant. The plant is quite useful fromeconomic point of view. Juice of flowers withsugar and black pepper is used in biliousnessand acidity. Seeds are used in aphrodis,fattening as external application to pains andleaves are purgative. Seeds contain fatty oil likearachis oil4-6.

In the present paper we want to showthe deleterious effects of chemical mutagenson the economically useful plant hibiscussabdariffa var. AMV1. Linn7.

MATERIAL AND METHODSDry and healthy seeds of diploid 2n = 72

yellow flowering variety of Hibiscus sabdariffavar. AMV

1 were used in all the experiments.

Mutagenic solutions of (EMS, NMG and dES)

were prepared just before the initiation of thetreatment in distilled water on a volumetricbasis8.Presoaking :

Dry seeds were soaked in distilled waterfor 6, 12 and 18 hrs. And then surface driedbefore mutagen treatment. Mutagen treatmentswere carried out at 27±20C with intermittentshaking. In the case of diethyl sulphatetreatment to maintain the concentrations, theaqueous solution of the mutagen was changedat half hourly intervals9,10.Post treatment washing and soaking :

At the end of the treatment, in each caseseeds were thoroughly washed four to fivetimes in running tap water and then post soakedin 20ml. of distilled water for one hour.Handling of treated seeds :

At the end of post treatment soakedseeds were thoroughly washed and sown inpetridishes and watered immediately.

Next day 100 seeds were sown in thefield with a spacing of four to six cm. betweenadjacent plants and 30 cm. between rows11,12.

In this paper pollen sterility percentageand seed set per capsule in M1 generation wereinvestigated. Pollen sterility was determined onthe basis of stainablity and shape of the pollengrains. Pollen grains which were fully stainedwith 2% acetocarmine, were scored as fertilewhile empty, partially stained and shriveledgrains were scored as sterile. The seeds at percapsule were determined by harvesting first 2capsules per plant.

The M2 population was screened formorphological mutations till the maturity of theplants.

Observations are given in Table 1,Table 2 and Table 3.

Key Words : Ethylmethane sulphonate, Diethyl sulphate, Floral variations,N-methyl-N-Nitro-N-nitrosoguanidine,


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Table 1 : Effects of EMS treatment in M1 generation

Treatments % Pollen sterility Seed set per capsule

Dry seed control - 25.6 Dry 3h 0.05% EMS 4.1 21.2

6h PSW control - 29.5 6h PSW 3h 0.05% EMS 27.8 19.6 12h PSW control - 29.3 12h PSW 3h 0.05% EMS 19.8 21.0 18h PSW control - 33.0 18h PSW 3h 0.05% EMS 3.1 29.2

Table 2 : Effects of NMG treatment in M1 generation

Treatments % Pollen Sterility Seed set per capsule

Dry seed control - 25.6

Dry 3h 0.1% NMG 50.9 15.2

6h PSW control - 29.5

6h PSW 3h 0.1% NMG 36.7 18.1

Table 3 : Effects of dES treatment in M1 generation

Treatment % Pollen sterility Seed set per capsule

Dry seeds control - 25.6 Dry 3h 0.1% dES 6.7 19.5 6h PSW control - 29.5

6h PSW 3h 0.1% dES 23.3 14.5 18h PSW control - 33.0

18h PSW 3h 0.1% dES 31.4 18.4

RESULTS AND DISCUSSIONM1 Effects on Pollen Sterility and SeedSetting

The effect of EMS on M1 parameterswith dry and presoaked seeds were given inTable 1. The pollen sterility graduallyincreased with the increase of the conc. of

EMS. The percentage of pollen sterility washighest i.e. 27.8% in 6h PSW + 0.05%. Thelowest number of seeds per capsule was 19.6seeds observed in 6h PSW + 0.05% EMS.According to Table 2, the percentage of Pollensterility increased with the increase of NMG.The highest % of pollen sterility was 50.9%


636

observed in dry seed + 0.1% NMG. In controlthe number of seeds per capsule was 25.6, 29.5,29.3 and 33.0 with dry 6, 12 and 18h PSWseeds respectively. The reduction in the numberof seeds was 16.8 seeds, highest in 12h,PSW+0.1% NMG treatment.

According to Table 3, maximum pollen

sterility 31.4% was obtained in 18h PSW +0.1% dES. The seed set per capsule decreasedwith the increase of dES concentrations. Thereduction in the number of seeds was maximum15.0 seeds in 6h PSW + 0.1% dES. Pollensterility and seed sterility also proved by Fig. 2and Fig. 3.

Fig. 1 : Control Plant

Fig. 2 : Essential Floral variants

a. Normal flowerb. Flower with free stigmatic

lobesc. Male sterile variantd. Non-stigmatic variante. Flower showing white

anthersf. A petal on stamianal tube.Above characters are related topollen sterility and seed sterility.

ae f

cbdab


637

Fig. 3 : Some other morphological variant : (a) Flower with seven petals (b) Flower with infinite number of petals and presence of a petal on staminal tube

(a) (b)

Fig. 4 : Green mutant : (1) Control (2,3) Green mutant

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CONCLUSIONIt is concluded that the deleterious effect

on the plant due to chemical mutagen treatmentclearly indicated by maximum pollen sterilityand reduction in seed setting. So it is necessaryto decide the dose which is not harmful to theeconomically important plant H-subdariffa var.AMV1 Linn.

REFERENCES1. Auerbach C., Mutation Research:

Problems, results and perspectivesChapman and Hall, London, 378-468,(1976).

2. Haarer A.E., Roselle-A Second Jutesubstitute, F.L.S. world crop. 4(2), 70,(1952).

3. Kamra O.P., On the differential mutagenicactivities of N-alkyl-N-Nitro-N-nitrosoguanide in higher plants. MutationRes. 13, 327-335, (1971).

4. Komarav V.L., Flora of the USSR Israelprogram for Scientific Translation, (1968).Kunkel. G., Plants for HumanConsumption, K Oeltz scientific Books,ISBN 3874292169, (1984).

5. Chopra R.N., Nayer S.L. and Chopra I.C.Glossary of Indian Medicinal plants.Council of Scientific and IndustrialResearch, New Delhi, (1986).

6. Manandhar N.P., Plants and people ofNepal Timber press, Oregon, ISBN 0-88192-527-6, (2002).

7. Kirtikar and Basu, Indian Medicinal plantsHibiscus sabdariffa, I , 330

8. Khalatkar A.S., Gopal A.R. and Ayengar,C.R. Bhatia, Modification of mutagenicefficiency of ethyl methane sulphonate.Mutation Research, 12, 331-334, (1971)

9. Konisht T., Studies on EMS inducedmutations in barley, I. Noguku Kenkyn,51, 209-220, (1967).

10. Lawley P.D., Methylation of DNA by N-methyl-N-nitrosoguanidine, Nature, 281,589, (1968).

11. Majumdar B., Induced leaf mutants ofrice. Ind. J.Genet. and Pl. Breed. 44,52-56, (1980).

12. Menzel M.Y. and Wilson F.D., Cyto-taxonomic relationships in Hibiscus sect.Furcaria (Abstr.), Amer. Jour. Bot., 48,535, (1961).

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deleterious effects of chemical mutagens on economically important

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