Effects of sulfur deficiency on non-protein nitrogen, soluble sugars, and N/S ratios in young corn (Zea mays L.) plants

Abstract

The concentrations of several N fractions, soluble sugars and N/S ratios were determined in Golden Bantam sweet corn and hybrid field corn grown in nutrient solutions and/or soil with various SO4-S levels provided. When the tevelof SOa-S supplied was less than that needed for maximum growth, higherthan-normal concentrations of amide (asparagine) N and lower-than-normal soluble sugar concentrations were found in the plants. An inadequate S supply appears to limit the plants capacity to synthesize protein to a much greater extent than it inhibits the nitrogen uptake mechanism.Total N/total S ratios (grammole basis) varying from over 100 to less than 15 were found in plants grown with different levels of sulfate supplied. When SO4-N, NO3-N, and the large amount of amide-N which accumulates under conditions of S deficiency are excluded, the ratio in young corn plants is generally between 22-50. The precision of the N/S ratio as an indicator of S adequacy for growing crops might be improved by a better understanding of the nature of the forms in which N and S occur in plants, and the effects of soil and plant factors other than S level. The percentage of amide-N shows promise as an indicator of S nutrient status. Data available indicates that added S will increase yields of corn plants if their amide-N level exceeds 500 ppm. Amide-N concentration correlates with N/S ratios, and it is much more readily determined than the latter. Its usefulness as a S nutrition indicator should be checked under field conditions.

Nutritional Relationship between Nitrogen and Sulfur in Cabbage (Brassica oleracea L. var. capitata L.)

“…As a result, soluble sugar concentrations in sulfur-deficient plants decrease, as has been reported for corn plants (6).…”

“…It (6). It is reasonable to consider both the nitrogen and the sulfur supply in diagnosing sulfur deficiencies.…”

The role of macronutrients in cabbage-head formation

“…It has been demonstrated that a suitable range of Ca : Mg ratio as well as adequate calcium and magnesium contents is necessary for the normal growth of corn (1) and cabbage (12) plants. When sulfur deficiency develops in cabbage plants, the N : S ratio increases because protein synthesis does not proceed efficiently and the nitrogen absorbed by the sulfur-deficient plants accumulates in the plant tissues as nitrates, amides and amino acids (8,13). As long as theN : S ratio remains within a suitable range (e.g.…”

“…As long as theN : S ratio remains within a suitable range (e.g. [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25] and the sulfur content is higher than the critical level for sulfur deficiency (Table 4), the sulfur nutrition of the cabbage plants can be considered to be normal. However, the fluctuations in the N : S ratio in the present experiments appear too large for it to be used as a guideline for diagnosing sulfur deficiency in cabbage plants, although the N : S ratio has been reported to represent a useful diagnostic tool for sulfur nutrition in some crops growing under given conditions (14).…”

“…The similar design throughout both sets of experiments enables us here to compare the roles of six macronutrients. In addition, the interactions between calcium and magnesium nutrition and between sulfur and nitrogen nutrition are briefly discussed, since supply of one of the two nutrients affects the nutrition of the other (1,8).…”