NITRATE REDUCTASE ACTIVITY ( NRA ) AT VEGETATIVE AND REPRODUCTIVE CONDI [ TIONS IN SACCHA RUM CULTIVAR CO
Regulations of flowering and induction of flowering in nonflowering clones of Saccharum has been found possible by the application of extra light (EL) and extra dark (ED) treatments. As to the effect of EL, ED and 'switch over' treatment from EL to ED on NRA relation to flowering NRA was found to be low at vegetative stage and as the plants reached the symptom stage. The activity reached a maximum value and thereafter showing a deckle with progress in flower development. Examination of gemplasm collection for NRA in clones of Saccharum species known to differ in their flowering behaviour was suggested.
MODIFICATION OF ECKERSON METHOD FOR DETERMINING NITRATE REDUCASE.
A satisfactory method for measuring the nitrate reduction by plant extracts should throw some light upon the ability of the plant to assimilate nitrogen in this form. A method for determining the nitrate reducing activity of plant extracts was worked out by ECKERSON.2 A brief statement of her method follows. Extracts of plant tissues are secured by grinding the fresh plant material very finely in a food chopper, and pressing out the juice through cheesecloth. One cubic centimeter of this juice and 1 cc. of 10 per cent. potassium nitrate solution containing 10 mg. of freshly dissolved glucose are made up to 10 cc. with water. This mixture is brought to a pH of 7.2 to 7.4 with sodium hydroxide, using phenol red as an indicator. In the original papers it was contended that there were enough natural buffers present to resist any great changes in hydrogen ion concentration; but, on the other hand, it was pointed out that there was a gradual increase in hydrogen ion concentration during the incubation period. The mixture is incubated under toluene at 350 C. for 17 hours. After incubation the amount of nitrite present is determined by the sulphanilic acid method. The writer and his coworkers found that, although the solutions used in the ECKERSON method were adjusted to the same pH at the beginning of the incubation period in the manner just described, there was an unequal decrease in pH, so that at the end of the period the extracts from different sources showed various degrees of acidity. Some of these extracts probably contained a greater quantity of a natural buffer. The change in pH can be prevented by substituting 4 cc. of 0.2 M phosphate buffer mixture (pH 7.3) for one-half of the water used in making up the original volume. The coloring matter in most plant tissues interferes with a comparison of the color produced by the nitrite reagent. It was found that by removing these colored substances with activated charcoal before treating with the sulphanilic acid reagent, a satisfactory comparison could be made. Upon being removed from the incubator the solutions are treated with 5 gm. of activated charcoal. After being thoroughly mixed and allowed to stand for 15 minutes they are washed through a fine filter paper into 100-cc. volumetric flasks. The flasks are made up to volume and 10-cc. aliquots are used in the determinations. None of the nitrite is absorbed. A standard solution of nitrite treated in the same manner was not affected by the charcoal, since the entire amount of nitrite could be recovered in the filtrate. For solutions which are difficult to clear with charcoal, a second clearing with 2 gm. of
Livestock Aspects of Feed Grain Policy
It is a signal event that our topic should be included on this program. In recent years, the livestock and poultry economy has scarcely been considered in the making of price and income policy for feed grains. It has been disregarded by pragmatic policy makers. It has been almost equally bypassed by theoretical economists, who usually kibitz freely. Policy for support and target prices for corn, grain sorghums, and other feed grains has been made with an eye almost exclusively fixed on the producers of those crops. The target price has been set relatively high in order to protect crop farmers' income. The latest (and current) loan rate policy has been to hold the rate low. Although a low rate facilitates moving grain into livestock and poultry consumption when crops are abundant, it does nothing to provide buffer stocks for years when crops are short. In addition, a couple of years ago it became administrative policy to dispose of the stocks inherited from an earlier period, even subsidizing their sale abroad. But the foremost example of one-sidedness is the attitude toward release prices. In all the rhetoric heard recently about the peril of holding corn or sorghums in reserve, the scold has been that release prices would not be set high enough. What group can the spokesmen have had in mind? Feed producers, of course! Not feed consumers, that is, livestock and poultry men. It has been a one-sided consideration of a two-sided issue. If all groups are to have equal voice in policy making, how can livestock and poultry interests be so ostracized? The one-sidedness has more impact now that so much livestock and poultry production has become detached from feed supply on individual farms. The livestock-poultry economy is therefore more sensitive to the availability and price of feed. It is in fact a contradiction that historically, livestock and poultry got more attention when they were still closely connected with feed production on the farm. In the early years of farm programs, the "ever-normal granary" was consciously designed to level out the supply and price of feed for livestock and poultry. Now that livestock and poultry have become more commercial and more vulnerable to a volatile feed situation, feed price stabilization has been progressively removed from the councils of farm policy. And the ultimate contradiction is that the alleged price-depressing perils of a feed reserve have been proclaimed in disregard of the fact that the main defense of feed grain producers' incomes is the target price-direct payment mechanism, not support prices. If grains on reserve should cause market prices to be reduced below target level, producers would get bigger direct payments, that is, producers with a base on their farm are protected in that way. Admittedly, production outside such a base would not be eligible for payment.