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.
Contributions to a biochemical study of sugarcane
SummaryFrom a study of the total iron (FeT), acid-soluble iron (FeS) and chlorophyll in the leaves of cane varieties, the fraction of iron bearing relation to chlorophyll (active iron, FeA) and that not related to chlorophyll (residual iron, FeR) have been calculated. FeR appears to bear relation to the growth of the cane varieties. A study of the variation of FeR/FeA ratio seems to be of help in determining whether the tendency of the plant, at a particular time, is more towards growth or accumulation of sucrose. It is shown that the factorf=FeR × FeS/FeA2 can serve as an index in the characterisation of cane varieties, in relation to early or late ripening character, even at an young age of 5 months.
QUANTITATIVE RELATION BETWEEN CHLOROPHYLL AND IRON IN GREEN AND CHLOROTIC PEAR LEAVES.
Lime-induced chlorosis is known to be curable by iron, and for this reason is attributed to iron deficiency. Chlorotic leaves should accordingly contain less iron than green leaves. It has been found by several investigators, however, that chlorotic leaves may contain more iron than green leaves. Similar results were obtained also by the writer, regardless of whether the iron content was reported on the dry or on the fresh-weight basis. No positive correlation could be observed between the iron content and the amount of chlorophyll of leaves obtained from chlorotic trees (table II, columns 4 and 5), although iron was the limiting factor in these leaves in so far as chlorophyll formation was concerned. This fact may be explained by either of the following hypotheses: 1. All the iron present in the leaves is equally (or nearly equally) active in chlorophyll formation. The efficiency of its activity, however, may vary considerably in leaves of the same tree. The green leaves would accordingly be those leaves which may contain small amounts of iron, but in which the efficiency of the iron in chlorophyll formation is very great. 2. Only a fraction of the iron in the leaves is active in chlorophyll formation. This active fraction is more abundant in the green leaves than in the chlorotic ones, although the reverse may be true in the case of the total amount of iron in the leaves.