The physiological assessment of the nutrient status of plants. II. The effect of the nutrient status of the plant with respect to phosphorus, sulphur, potassium, calcium, or boron on the pattern of leaf area response following the transfer to different nutrient solutions

1966 ◽  
Vol 17 (5) ◽  
pp. 633 ◽  
Author(s):  
D Bouma ◽  
EJ Dowling

In a series of experiments, young subterranean clover plants were raised at several levels of phosphorus, sulphur, potassium, calcium, or boron respectively, and then transferred to complete nutrient solutions and to solutions without the previously varied element. Response patterns based on relative leaf area increases revealed quantitative relations with the nutrient status of the plants at transfer in the experiments with different phosphorus, potassium, or boron levels. In the sulphur experiment the response pattern indicated only the presence or absence of stress. In the calcium experiment the picture was somewhat obscured by premature death of leaves following collapse of the petioles. In a second series of experiments it was shown that the presence or absence of specific stresses could be determined from the patterns of leaf area response after transfer of plants to complete solutions and to solutions each without one of the five elements.

1967 ◽  
Vol 18 (2) ◽  
pp. 223 ◽  
Author(s):  
D Bouma ◽  
EJ Dowling

Experiments were carried out with subterranean clover in water cultures to study the effect of interactions between phosphorus, sulphur, and nitrogen. These elements were varied in pairs, and leaf area responses measured after transfer to complete solutions and to solutions without one of the two previously varied elements. Leaf area responses after transfer of plants deficient in phosphorus as well as in sulphur revealed both deficiencies when they had been of approximately equal intensity. When elements were deficient to differing degrees, leaf area responses depended on the relative intensities of the deficiencies. With deficiencies of sufficiently differing intensities, leaf area response patterns after transfer showed a deficiency of only one element because its supply had been low enough to mask the effect of the other deficiency. Transfer of plants deficient in only one element confirmed that there is no simple relation between the nitrogen status of the plant and the induced leaf area responses. The results also confirmed the feasibility of at least a qualitative assessment of the phosphorus or the sulphur status of plants.


1966 ◽  
Vol 17 (5) ◽  
pp. 647 ◽  
Author(s):  
D Bouma ◽  
EJ Dowling

Young subterranean clover plants were raised at several levels of nitrogen supply, and then transferred to complete solutions and to solutions without nitrogen Subsequent leaf area response patterns were not related to the supply of combined nitrogen before transfer. The relative differences m leaf area between the two solutions were thought to depend on differences In nodulation caused by differences In the supply of combined nitrogen before transfer. Further experiments showed that the rates of leaf area Increase of inoculated and well-nodulated plants In solutions without nitrogen were similar to those of corresponding plants receiving combined nitrogen Plants that had not been inoculated showed markedly smaller leaf growth rates after transfer to solutions without nitrogen than in complete solutions Even when the previous supply of combined nitrogen had been adequate, plants transferred to solutions without nitrogen were unable to maintain leaf area Increases at rates comparable with those of the corresponding plants in complete solutions for more than 3 days. Reasons for the marked differences between these results and those of experiments with phosphorus, sulphur, potassium, and boron are discussed


1962 ◽  
Vol 13 (5) ◽  
pp. 791 ◽  
Author(s):  
D Bouma ◽  
EJ Dowling

Subterranean clover plants of different phosphorus status, obtained from pastures or raised in the glass-house, were transferred to nutrient solutions. These included a complete solution, and others each lacking a different element. Subsequent response patterns were defined by leaf area changes. Plants raised at low phosphorus levels showed considerably smaller increases in leaf area in the solutions without phosphorus than in the other solutions. These differences were discernible as early as 2 days after transfer. There was little difference between the control treatments and treatments omitting elements other than phosphorus. Plants raised at a more adequate phosphorus level did not show differences between treatments till much later. The results are discussed, and their use as a basis for a simple method of determining the nutrient status of plants is indicated.


1972 ◽  
Vol 25 (6) ◽  
pp. 1147 ◽  
Author(s):  
D Bouma ◽  
EAN Greenwood ◽  
EJ Dowling

During the first 3 days after transfer of moderately sulphur-deficient plants (S1) to full nutrient solutions, the relative growth rate (Rw) was considerably lower than that of plants raised at higher sulphur levels (S2 and Sa). This was reflected in a lower leaf area ratio of the S1 plants, and particularly in a reduction of nearly 50% in the net assimilation rate (EA). Net losses in dry matter from younger emerged leaves and petioles accounted for 25% of the dry matter in new leaves and petioles of S1 plants produced during this period.


1956 ◽  
Vol 7 (2) ◽  
pp. 98 ◽  
Author(s):  
JN Black

Changes in the pre-emergence distribution of dry matter in subterranean clover (Trifolium subterraneum L.) variety Bacchus Marsh were followed at 21°C, using three sizes of seed and three depths of sowing, ½, 1¼, and 2 in. Decreasing seed size and increasing depth of sowing both reduce the weight of the cotyledons a t emergence. Seed of the three sizes were sown a t three depths in pot culture a t staggered intervals so that emergence was simultaneous. Dry weight in the early vegetative stage was proportional to seed size, and total leaf area and leaf numbers showed similar trends. Plants of each seed size grew at the same relative rate. No effect of depth of sowing could be detected, and this was shown to be due to the cotyledon area a t emergence being constant for any given seed size, regardless of varying depth of sowing and hence of cotyledon weight. It was concluded that seed size in a plant having epigeal germination and without endosperm is of importance: firstly, in limiting the maximum hypocotyl elongation and hence depth of sowing, and secondly, in determining cotyledon area. Cotyledon area in turn influences seedling growth, which is not affected by cotyledon weight. Once emergence has taken place, cotyledonary reserves are of no further significance in the growth of the plants.


Author(s):  
Antonio F. Monteiro Filho ◽  
Márcia R. Q. A. Azevedo ◽  
Carlos A. V. de Azevedo ◽  
Josely D. Fernandes ◽  
Carisa R. da Silva ◽  
...  

ABSTRACT The objective of this study was to evaluate the growth of crisp lettuce in hydroponic cultivation, following the nutrient film technique (NFT), using optimized mineral and organomineral nutrient solutions. The experiment was set in 8 x 3 factorial scheme, with treatments distributed in randomized blocks and split plots, with three replicates. The plots corresponded to eight nutrient solutions, of which four were mineral solutions with chemical composition suggested by Bernardes, Furlani, Castellane & Araújo and Ueda, and four were organomineral solutions, suggested by this research with chemical composition similar to those of the previously mentioned mineral solutions. The subplots corresponded to three varieties of crisp lettuce: Thaís, Vanda and Verônica. At 25 days after transplanting, the following parameters were evaluated: stem and crown diameter, root length, leaf area and number of leaves. For stem and crown diameters and number of leaves, the mineral solutions promoted the highest means. The mineral solution of Furlani and the organomineral solutions, except the modified solution of Castellane & Araújo, promoted the greatest root lengths. The smallest leaf area was obtained in the organomineral solution of Ueda. The cultivar Verônica had the highest root length and stem diameter.


1995 ◽  
Vol 125 (2) ◽  
pp. 175-182 ◽  
Author(s):  
J. M. Ramos ◽  
I. De La Morena ◽  
L. F. Garcia Del Moral

SUMMARYNitrogen is an important factor determining grain yield of barley (Hordeum vulgare L.). Optimal rates and application timing can vary according to the environmental conditions under which the crop is grown. For 8 years (1979–86) barley yield, tillering, and leaf-area response to N application rates and timing were studied in southern Spain. The results showed that, under our experimental conditions, the most advantageous N rate for grain yield was 60 kg/ha, either split equally between sowing and tillering, or else with the greater proportion applied at tillering. Nitrogen applied at sowing increased number of tillers per plant, and N applied at tillering favoured tiller survival for later spike formation. In addition, N applied at tillering increased the number of leaves per plant, leaf area per plant, and the leaf area index, the maximum value of which occurred at anthesis.


1976 ◽  
Vol 3 (4) ◽  
pp. 527 ◽  
Author(s):  
S Fukai ◽  
JH Silsbury

Subterranean clover communities were grown in temperature-controlled naturally lit glasshouses at 15, 20, 25 and 30�C. Dry matter yield, leaf area and the distribution of dry matter between plant parts were determined at about 14-day intervals for up to 130 days from planting. Leaf appearance, leaf death, leaf number and growth of laterals were observed for individual plants in the community over a similar time period. A logistic growth curve was found for each temperature and crop growth rate calculated from the equation fitted for each growth curve. The optimum temperature for growth was relatively high (20-25°C) when plants were young, but decreased during growth so that after 100 days total dry matter was inversely related to temperature over the range 15-30°C. Both the rate of leaf appearance and the rate of leaf death on the main stem were constant at each temperature during the experimental period and were directly related to temperature. The number of leaves per unit ground area was determined mainly by the rates of leaf appearance and leaf death on the main stem, since the contribution of laterals was small. The proportion of stem and petiole to total dry matter increased, and that of green leaf lamina decreased, with increase in total dry matter. Neither was markedly affected by temperature. An inverse relationship between specific leaf area and temperature resulted in a lower ratio of leaf area to total dry matter at 15°C compared with that at 20, 25 or 30°C.


1960 ◽  
Vol 11 (3) ◽  
pp. 277 ◽  
Author(s):  
JN Black

Three strains of subterranean clover differing in leaf development were grown in pure swards and in all combinations in mixtures. The strain Yarloop has relatively few large leaves held on long petioles; Tallarook has many small leaves and short petioles; Bacchus Marsh is intermediate in all these respects. The swards were grown in boxes and were sampled on four occasions during the period of vegetative growth. Leaf area in each 2 cm layer of the sward was determined separately, and for both strains in the mixed swards, and measurements of the light intensity reaching each layer were obtained. Root weights were determined for all swards and separately for each component of the mixed swards. Examination of the dry weights showed that the growth of the strain having the lesser petiole elongation was suppressed. In the extreme instance Tallarook was so suppressed when grown with Yarloop that in the final inter-sampling period it grew completely in the dark, and lost about half its dry weight. Bacchus Marsh also suppressed Tallarook, but to a lesser extent, while Bacchus Marsh was itself suppressed in competition with Yarloop. The amount of light energy intercepted by the two components of the mixed swards was calculated from the leaf area and light profiles, and confirmed the importance of the spatial distribution of leaves in plant competition. It was concluded that, in the absence of defoliation, the success of a strain under competition was associated with its potential petiole elongation.


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