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Letter to the Editor

NMR -- An Eye to the Plant Breeder

Sir,

S r i n i v a s a n et al. (1) have misled readers by po in t ing out t h a t while e s t ima t ing oil in oilseeds by pulsed NMR, the effect of r e l axa t ion t ime ha s no t been con- sidered in our Inst i tute . The fact is, the effect of iodine va lue (IV) of oils on NMR response ha s been men- t ioned (2,4) by s t a t i ng t ha t for correct NMR ana lys i s of the oil con ten t of seed, the i n s t r u m e n t mus t be cali- b ra ted wi th seed of the same va r i e ty as the samples and thei r f a t t y acid composi t ion should be similar. A corre la t ion between re laxa t ion t ime and IV by Tiwar i et al. (3) has been established. Based on that , the e r ror in t roduced on oil es t imat ion due to such varia- t ion in re laxa t ion t imes has been calculated a n d repor ted (4).

F u r t h e r f rom the da t a presented by S r i n i v a s a n et al. (1), a l inear corre la t ion coefficient of +0.72 between oil con ten t and re l axa t ion t imes of co t tonseed sam- ples has been ob ta ined by me. I t m a y be due to protein-oil in te rac t ion (5) and qual i ty of oil in oilseeds (3,4). Based on that , oil and protein content and wa te r a n d protein conten t in oilseeds (due to protein wa te r in terac t ion) can be es t imated f rom thei r r e l axa t ion t imes by a sui table ca l ibra t ion graph .

T h e s t and a rd i za t i on work done by T iwar i an d Burk (6) a n d G a m b h i r and A g a r w a l a (7) is based on the a s sumpt ion t h a t the r e l axa t ion t imes of oil in oilseed r e m a i n s cons tan t , which is con t r a ry to the h i s tog ram of r e l axa t ion t imes var ia t ion vs number of oilseed samples presented (8).

In addi t ion, G a m b h i r and A g a r w a l a (7) have never t a k e n into cons idera t ion the po in t m a d e (9), t h a t is, " I t is not clear if the der ived componen t s represen t d i f fe ren t phases of wa te r or mere ly to p a r a m a t e r i z e a con t inuous d is t r ibut ion of wa te r molecule mobil i t ies a n d r e l axa t ion t imes ." G a m b h i r et al. (10) h a v e re- p roduced the work of Yu. G. Kulesh and A.M. Cher- n i t y n (11) wi thou t acknowledg ing the i r work. T iwar i et al. (12), while cor re la t ing the d rough t - res i s t an t var- ie ty of millet pearl , whea t and rice wi th the re laxa t ion t ime hav e men t ioned t ha t the effect of p a r a m a g n e t i c ions on spin lat t ice r e l axa t ion t ime of m a n y p l an t

t issues was fbund to be a lmos t negligible, which is c o n t r a r y to the f ind ings of Su ja t a G o p a l a k r i s h n a et al. (13) and G a m b h i r (14).

In spi te of the l imi ta t ion of oil e s t imat ion by NMR due to the va r i a t i on in r e l axa t ion t imes, N MR can still be used as a n eye to the p lan t breeder.

T.S. Ra j an 12/4 W.E.A. Karol B a g h New Delhi P I N 110005 Ind ia

REFERENCES

1. Srinivasan, V.T., B.B. Singh, P.R. Chidambaraeswaran and V. Sundaram, J. Am. Oil Chem. Soc. 62:1021 (1985).

2. Robertson, J.A., and W.H. Morrison, Ibid. 62:961 (1979). 3. Tiwari, P.N., P.N. Gambhir and T.S. Rajan, J. Magn.

Reson. 15:292 (1974). 4. Rajan, T.S., National Academy Science Letters 2, No. 3, 109

(1979). 5. Deese, A.J., Edward A. Dartz, Lizz Hymal and Sidney

Fleisher, Biophys. J. 37:207 (1982). 6. Tiwari, P.N. and W. Burk, J. Am. Oil Chem. Soc. 57:119

(1980). 7. Gambhir, P.N., and A.K. Agarwala, Ibid. 62:103 (1985). 8. Tiwari, P.N., P.N. Gambhir and T.S. Rajan, Ibid. 51:104

(1974). 9. Proceedings of the second international conference on water

and ions in Biological systems -- held September 6-11, 1982 in Bucharest Romania, under the auspices of UNESCO (pages 10,41, 269 and 295) edited by Alberte Pullman, V. Valilescu and L. Packer -- Plenum Press N.Y. -- London.

10. Gambhir, P.N., B.C. Panda and R.K. Purl, Ind. J. Expl. Biology 19:790 (1981).

11. Kulesh, ¥u. G., and A.M. Chernityn, Soviet Plant Physiol- ogy 51:881 (1971).

12. Tiwari, P.N., P.N. Gambhir, K.K. Nath and S.S. Chahal, J. Nuclear Agric. Biol. 15:128 (1986).

13. Gopalakrishna, Sujata, S.S. Ranade, V.T. Srinivasan, B.B. Singh, V.K. Panday and G.V. Talwalkar, Indian J. Exp. Biology 22:407 (1984),

14. Gambhir, P.N., J. Nucl. Agric. Biol. I0:39 (1981).

[Received April 7, 1987; accepted April 29, 1987]

JAOCS, Vol, 65, no. 2 (February 1988)