Browsing by Author "K.N. Lal"

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A rapid method of leaf area determination
(1951) K.N. Lal; M.S. Subba Rao
RECENT physiological studies on nutrition and growth have shown that leaf area is a reliable index of growth factors determining dry matter accumulation, carbohydrate metabolism, yield and quality of crops1-9,12. Various methods have therefore been devised for measuring the total leaf surface on a growing plant. Of these, mention may particularly be made of:(1) methods based on tracing individual leaves and determining their respective area by planimeter; (2) use of sensitized photopapers, (3) photo-electric devices of various types, (4) adoption of cardboards of known area approximating to the area of different type leaves, and lastly (5) use of mathematical formulæ based on certain leaf measurements. The utility of one or the other of these methods has been stressed by different investigators. © 1951 Nature Publishing Group.
Absorption and accumulation of potassium in component parts of sugarcane as affected by age, phosphorus deficiency and phosphorus fertilization
(1961) J.N. Singh; K.N. Lal
[No abstract available]
Development of assimilating surface in relation to leaf indices and dry matter accumulation
(1955) M.S. Subba Rao; K.N. Lal
[No abstract available]
Elemental composition of Sugar-cane leaf and stem in relation to nitrogen deficiency
(1951) K.N. Lal; Rajat De
NITROGEN deficiency has been known to bring about certain specific changes in growth, physiology and composition of sugar-cane plants1,2. Its effect on mineral composition is less clearly understood. To throw light on this problem, sugar-cane variety Co 453 was grown in (1) Hoagland's complete nutrient culture, and (2) Hoagland's nitrogen-deficient culture for the entire life-cycle3. Percentages of nitrogen, P2O5, K2O, calcium, magnesium and sulphur in sugar-cane leaf and stem were estimated at maturity according to standard methods of analysis and expressed as percentages of dry weight. © 1951 Nature Publishing Group.
Investigation of the effect of age on assimilation of leaves
(1935) B.N. Singh; K.N. Lal
[No abstract available]
Photosynthetic specificity in relation to biochemic constitution of leaves
(1938) B.N. Singh; K.N. Lal; K. Prasad
An attempt has been made in this paper to study the photosynthetic activity of a number of plant species under optimum yet identical conditions of factor-intensity and to trace the relationship, if any, between the organic materials subsequently formed and the assimilatory influx of carbon dioxide. Different plant species have different photosynthetic rates, the range of variation from species to species becoming more and more pronounced with advance in age of plants. Such variations under otherwise constant external conditions are discussed with special reference to internal factors. The water-content of the experimental material no doubt differs from plant to plant but does not follow the same gradation as that maintained by assimilation rate. The chlorophyll content too shows no correlation with the assimilatory efficiency. There seems to be a fair degree of correlation between the products economised in leaves during their photosynthetic activity and the products stored by the same species towards the close of the life-cycle. Plants economising sugars, proteins, starches and fats in assimilating leaves also store such substances respectively in their storage organs towards the close of their life-cycle. The photosynthetic rate seems to be related to the nature of the end products accumulating in assimilating leaves. Leaves accumulating simpler sugars have fairly high rates of assimilation while those economising the more complex starches, proteins and fats respectively have to their credit decreasing assimilatory efficiency. The biochemic constitution of the experimental material as judged by the products economised during assimilation appears to be an important internal factor governing photosynthesis and suggestively explains the phenomenon of photosynthetic specificity in certain groups of crop plants. © 1938 Indian Academy of Sciences.
Studies in crop physiology - Deficiency-sufficiency effects of fertilisers upon growth and protein content of wheat
(1946) K.N. Lal; Sati A. Malkani; H.S. Pathak
[No abstract available]
Studies in crop physiology - Effect of farmyard manure and castor cake upon development, yield and seed quality of wheat
(1951) K.N. Lal; B.S. Yadav
[No abstract available]
Studies in crop physiology - Effect of nitrogen, phosphorus and potassium deficiencies on respiration rate of sugarcane leaves
(1951) K.N. Lal; Rajat De; M.S.Subba Rao
The paper narrates the results of an experimental enquiry on respiration rate of sugarcane leaves of different stages of development under four conditions of nutrition, viz., complete nutrition, nitrogen deficiency, phosphorus deficiency and potassium deficiency. The experiments were conducted at maturity stage on five varieties of sugarcane, e.g., Co 453, Co 421, POJ 2878, Co 205 and Rheora grown in sand in pots. Co 205 and Rheora show high leaf respiration as compared with Co 453 and POJ 2878, having significantly lower respiration rates. No differences in leaf respiration upto the third or fourth leaf stage are noted; beyond this the greater the stage of leaf development, the lower is the respiration of leaves. Nutritional conditions bring about considerable changes in respiration of leaves. Thus nitrogen deficiency shows normal leaf respiration at maturity as compared with either phosphorus or potassium deficiency, each of which exhibit supernormality in respiration. Variations in respiration rate under these conditions appear to be determined by changes in chemical composition of leaves, particularly nitrogen and carbohydrate fractions. Observed differences in respiration are discussed in the light of such changes. © 1951 Indian Academy of Sciences.
Studies in crop physiology - Interrelation between leaf area, leaf indices and drought resistance in sugarcane
(1950) K.N. Lal; O.N. Mehrotra
This paper elucidates the interrelation between leaf area and other leaf characteristics in six varieties of sugarcane grown under field conditions. Relation between these features and drought resistance in sugarcane is also analysed. Drought-resistant behaviour of Rheora is associated with poor leaf surface and small size of leaves. Co 205 approaches this variety most in the characteristics of its leafy growth. Leaf surface expansion is found to be determined by three conditions, namely, increase in (i) leaf length, (ii) leaf width and (iii) dry weight of leaves. High positive correlation between these factors and leaf area indicates that these characteristics are highly correlated. The possibilities of water content showing negative correlation with leaf area is also pointed out. Relation between leaf area and linear measurements of length and breadth is expressed by the following two equations: For a single leaf:- Log A = Log L + Log B + Log K (1) For a population of leaves:- Log Σ A = Log Σ L + Log ΣB + Log K - Log N, (2) where A is leaf area, L = leaf length, B is leaf breadth, K is leaf factor and N is number of leaves. The leaf factor K appears to be an important physiological constant representing the relation between linear growth (L x B) and leaf area. Its relatively low value in drought-resistant Rheora and also in Co 205, as against its relatively high value in other varieties with high leaf indices- Co 290, Co 453, Co 385 and Co 312-is characteristic. © 1950 Indian Academy of Sciences.
Studies in crop physiology - Nutrient effects upon development and vegetative vigour of sugarcane
(1949) K.N. Lal; Shankarji Shrivastava
[No abstract available]
Studies in crop physiology - On some physiological attributes of transpiring surface in relation to drought resistance in sugarcane
(1950) K.N. Lal; O.N. Mehrotra
[No abstract available]
The influence of artificial fertilisers upon the photosynthetic efficiency of Andropogon sorghum
(1939) B.N. Singh; K.N. Lal; M.B. Lal
The influence of fertilizers upon photosynthesis, chlorophyll content and respiration rate of Andropogon sorghum (Var. Cawnpore 46) has been studied under ifferent combinations and levels of manuring. When supplied singly potassic and phosphoric fertilizers are much more useful than the nitrogenous in increasing the photosynthetic efficiency of leaves. In all these cases photosynthesis rises with increasing supply of fertilizers upto a certain optimal level, later showing a decline. In the three fertilizer series the rate of photosynthesis never reaches the same level as that recorded for optimal doses of potash and phosphates applied singly. The association of the three ingredients N2, P2O5 and K2O appears to slacken the rate of CO2 intake by leaves. When one or the other nutritive ingredient is either reduced or completely removed, this deleterious influence is partly overcome and photosynthesis increases. The influence of fertilizers upon respiration, photosynthesis (both apparent and real) and chlorophyll is practically of the same nature, inasmuch as, augmentation in assimilatory activity in majority of cases is also followed by an increase in chlorophyll content and respiration rate. Photosynthesis in different series of cultures does not rise with the increase in the chlorophyll content upto a critical limit of 2.0 mgm./fresh weight. Beyond this level, however, increase in chlorophyll is always associated with acceleration in photosynthetic activity. The variation in assimilation number in different series of experiments indicates that chlorophyll is not the only factor controlling photosynthesis. Photosynthetic augmentation under the influence of fertilizers may be due to (i) increased chlorophyll formation which in its turn influences carbohydrate metabolism, (ii) direct supply of mineral ingredients, nitrogen, phosphorus and potassium for proper functioning of leaf material and (iii) the increase in respiratory activity of leaves which considerably influences the rate of real assimilation. © 1939 Indian Academy of Sciences.
Uptake of phosphorus and its accumulation in component parts of sugarcane as affected by age, phosphorus deficiency and levels of phosphorus
(1961) K.N. Lal; J.N. Singh
[No abstract available]