Physiological and ecological studies on the oestrogenic isoflavones in subterranean clover (T. subterraneum L.) IV. Effects of zinc deficiency in clover seedlings.

1967 ◽  
Vol 18 (1) ◽  
pp. 39 ◽  
Author(s):  
RC Rossiter

Results of a glasshouse experiment, conducted on an acutely zinc-deficient soil, are presented. At day 29, the cotyledons and unifoliate leaves of zinc-deficient plants showed higher isoflavone concentrations, and markedly higher total isoflavones per leaf, than did those of plants supplied with zinc. At day 47, however, when the "little leaf" condition was well advanced in the zinc-deficient plants, trifoliate leaves of the deficient plants were lower in isoflavone levels (and especially in isoflavones per leaf) than those of normal plants. The patterns of isoflavone distribution correspond with, and are thought to result from, effects of zinc deficiency in the seedling stage on photosynthetic accumulation in plant parts. It is considered that zinc deficiency in the field is unlikely to affect the incidence of "clover disease".

1982 ◽  
Vol 33 (6) ◽  
pp. 989 ◽  
Author(s):  
DJ Reuter ◽  
JF Loneragan ◽  
AD Robson ◽  
D Plaskett

Effects of zinc supply on the distribution of zinc and dry weight among plant parts were examined during the first 55 days of vegetative development of Seaton Park subterranean clover grown in a zinc-deficient soil in a glasshouse. Symptoms of zinc deficiency first appeared in young trifoliate leaves. Zinc deficiency decreased the expansion of blades and petioles, delayed the development of leaves and lateral branches, depressed dry weights of roots and shoots, and increased the proportion of plant dry weight in roots and leaf blades. In each treatment and at each harvest, zinc concentrations varied widely amongst plant parts and with their physiological age. Plant parts also differed widely in the response of their dry matter and zinc concentrations to both zinc treatment and harvest time. It is suggested that these complex relationships explain why plant samples consisting of composite plant parts are not suitable for diagnosis of zinc deficiency. In the present experiment, zinc concentration in whole shoots was unsatisfactory for diagnosing zinc deficiency since concentrations were higher in young, zinc-deficient plants than in older, zinc-adequate plants. In young leaf blades of the same physiological age, zinc concentrations showed reasonably constant relationships with plant growth throughout the entire experiment. However, they varied two- to three-fold in leaves of different ages from the same plants. The results show the importance for diagnosis of zinc deficiency of selecting as a sample a single organ of defined physiological age. The youngest open leaf blade is recommended for diagnosis of zinc deficiency in subterranean clover.


1982 ◽  
Vol 33 (6) ◽  
pp. 1001 ◽  
Author(s):  
DJ Reuter ◽  
JF Loneragan ◽  
AD Robson ◽  
D Plaskett

The effect of phosphorus on the relationship of zinc concentrations in various plant parts to yield of Seaton Park subterranean clover was examined. Plants were grown in a glasshouse at three levels of phosphorus (39, 65 and 130 mg phosphorus/pot; denoted P1, P2 and P3 respectively) and six levels of zinc added in factorial combination to a sand deficient in both phosphorus and zinc. At the lowest three levels of zinc supply, plants were severely to moderately deficient in zinc: in them, increasing levels of phosphorus depressed growth and induced high concentrations of phosphorus (> 1 % DM) in several plant parts and symptoms of phosphorus toxicity in leaves. At the highest three levels of zinc supply, plants at P1 were phosphorus deficient: application of P2 and P3 increased growth and induced zinc deficiency primarily by diluting the available zinc. In addition, P3 appeared to depress slightly the zinc content of plant tops by another mechanism. In severely zinc-deficient plants, phosphorus supply changed the relationships between zinc concentrations in various plant parts and yield of whole tops, probably as the result of phosphorus toxicity. In the youngest open leaf blades, an asymptotic relationship at P1 changed at P2 and P3 to sigmoidal and to 'Piper-Steenbjerg' relationships respectively. These changes would not have invalidated the use of plant analysis for diagnosing zinc deficiency. In moderately zinc-deficient plants, phosphorus supply had little or no effect on the relationships of zinc concentration in plant parts to yield of shoots. As a result, critical concentrations in plant parts generally remained constant over the whole range of phosphorus supply. The data refute suggestions that high levels of phosphorus in plant parts inactivate the zinc within them, thus removing a potential problem in the use of plant analysis for diagnosing zinc deficiency in subterranean clover. The results confirm the previous suggestion that a concentration range of 12-14 �g zinc/g in the youngest, open leaf blade is critical for diagnosis of zinc deficiency in subterranean clover.


1960 ◽  
Vol 11 (2) ◽  
pp. 162 ◽  
Author(s):  
DS Riceman ◽  
GB Jones

Young plants of subterranean clover (T. subterraneum L. var. Bacchus Marsh) were grown between day 20 and day 43 in culture solutions containing zinc labelled with the radioactive isotope 65Zn and were then transferred to zinc-free culture solution. The distribution of labelled zinc in the plant parts during the subsequent onset of zinc deficiency was determined by means of radioautographs. By similar means the distribution of labelled zinc was determined in plants transferred to culture solutions containing inactive zinc. The zinc present in fully expanded living leaves was largely retained there while they remained alive, even during the onset of zinc deficiency which progressed to the "little leaf" stage. Some zinc was transported out of these leaves when they became prematurely senescent as a result of the deficiency. During the onset of the deficiency some zinc was transported out of the roots and the main axis. After zinc deficiency had become acute and growth had practically ceased, the concentration of zinc in the youngest leaves at the growing points of the main axis and runners remained higher than that in the slightly older, fully expanded leaves.


1990 ◽  
Vol 30 (4) ◽  
pp. 557 ◽  
Author(s):  
JD Armour ◽  
AD Robson ◽  
GSP Ritchie

Navy beans (Phaseolus vulgaris cv. Gallaroy) were grown with 7 rates of zinc (Zn) in a Zn-deficient gravelly sandy loam in a glasshouse experiment. The plant shoots were harvested 31 days after sowing and the Zn concentration in each of 4 plant parts (YL, young leaf; YOL, young open leaf; YFEL, youngest fully expanded leaf; and whole shoots) was related to the fresh weight of the shoots. The critical Zn concentrations (mgtkg) in the plant parts determined by the 2 intersecting straight lines model were 21.1 for YL (r2 = 0.66), 17.1 for YOL (r2 = 0.83), 10.6 for YFEL (r2 = 0.91) and 12.5 for the whole tops (r2 = 0.88). The YFEL was selected as an appropriate diagnostic tissue because it is readily identifiable in the field and had the highest 1.2 with fresh weight. In a second glasshouse experiment, the critical Zn concentration in the YFEL and 5 soil tests were evaluated for their ability to predict the Zn status of navy beans. There were 13 soils from sands to clays with a wide range of chemical properties. The soil tests were 0.1 mol/L HCl, DTPA, EDTA, dilute CaCl2 and soil solution Zn. The concentration of Zn in the YFEL correctly predicted Zn deficiency or adequacy in about 77% of samples. The results from both experiments showed that a critical Zn concentration of 10-11 mg/kg in the YFEL can be used to diagnose the Zn status of Gallaroy navy beans. It was not possible to recommend a single soil test for prediction of the relative yield of navy beans. A combination of quantity (HCl, EDTA, DTPA) and intensity (soil solution, 0.002 mol/L CaCl2, 0.01 mol/L CaCl2) parameters were able to explain most of the variation in the Zn concentration of the YFEL, a more sensitive measure of nutrient availability than relative yield. EDTA-Zn in combination with 0.01 mol/L CaCl2-Zn explained 90% of the variation in the Zn concentration in the YFEL, while HCl- or DTPA-Zn and 0.01 mol/L CaCl2 explained about 80% of the variation. As soil solution Zn was significantly correlated with 0.002 and 0.01 mol/L CaCl2-Zn (r = 0.75, P<0.01; r = 0.62, P<0.05, respectively), CaCl2-Zn may be used as a more convenient measure of Zn intensity than soil solution Zn.


Soil Research ◽  
2000 ◽  
Vol 38 (3) ◽  
pp. 735 ◽  
Author(s):  
Robert Summers ◽  
Martin Clarke ◽  
Tim Pope ◽  
Tim O'Dea

Bauxite residue from alumina refining was used to coat granules of single superphosphate to reduce the leaching of phosphorus in coarse, sandy soils for pastures in high rainfall areas of south-western Australia (>800 mm annual average). The impact of coating the superphosphate on the leaching of phosphorus was measured in a glasshouse experiment and the effectiveness of the fertiliser using dry herbage yield of subterranean clover (Trifolium subterraneum) was measured in a field experiment. The glasshouse experiment measured the effect of coating the superphosphate with bauxite residue at 0, 5, 10, 15, 20, 25, 30, 35, and 40% by weight. A coating of 25% (by weight) was chosen for the field experiment. In the glasshouse experiment, the coated granules were applied to columns of soil, where subterranean clover was grown under leaching conditions. A coating of 30%, by weight, reduced leaching of single superphosphate by about half. Increasing the coating of bauxite residue also increased the phosphorus uptake and increased the plant growth. In the field trial, the effectiveness of single superphosphate with a bauxite residue coating of 25% by weight was increased on average by 100% in Year 1, 303% in Year 2, and 158% in Year 3, relative to freshly applied single superphosphate. The bauxite residue coating also increased the phosphorus content of the herbage in a similar manner to the increases in yield. Limited soil phosphorus tests showed only minor increases in the residues of phosphorus where the superphosphate had been coated with bauxite residue.


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.


1969 ◽  
Vol 20 (6) ◽  
pp. 1043 ◽  
Author(s):  
RC Rossiter

In experiments with young plants of the Dwalganup strain of subterranean clover, nitrogen deficiency was associated with increased concentrations of isoflavones in the expanded leaves and cotyledons. In the first trifoliate leaves the concentration of total isoflavones (formononetin+genistein+ biochanin A) was approximately doubled at low nitrogen supply. Biochanin A was much less affected than the other two isoflavones. The increase in isoflavone contents of nitrogen-deficient leaves was associated with decreased protein synthesis, but not always with increased sugar contents. The supply of carbon substrates for isoflavone synthesis may depend on starch as well as sugar contents. Practical implications of the results are considered briefly.


1967 ◽  
Vol 18 (1) ◽  
pp. 23 ◽  
Author(s):  
RC Rossiter ◽  
AB Beck

Isoflavone levels in subterranean clover leaves were higher in 13 hr days of natural daylight than in 6 hr days, but length of photoperiod per se had no substantial effect on these levels. In the field, reduction of light intensity (by shading) to 40% daylight caused no decline in isoflavone levels compared with full daylight; even at 24% daylight the reduction in levels was ill defined. On the other hand, in young seedlings there was a marked fall in isoflavone content, especially in the unifoliate leaf, as light intensity fell from 950 to 320 f.c. However, appreciable isoflavone formation was found in dark-grown clover seedlings. Possible light reactions connected with the promotion of isoflavone synthesis are discussed. Changes in isoflavone levels resulting from variation in the natural light environment are unlikely to be sufficient to affect "clover disease".


1981 ◽  
Vol 32 (2) ◽  
pp. 257 ◽  
Author(s):  
DJ Reuter ◽  
AD Robson ◽  
JF Loneragan ◽  
DJ Tranthim-Fryer

Effects of severe and moderate copper deficiency on the development of leaves and lateral branches, on the distribution of dry weight within the plant, and on seed yield of Seaton Park subterranean clover were assessed as part of three glasshouse experiments. Copper deficiency markedly depressed top and root growth without producing any distinctive symptoms. It retarded phasic development by delaying development of leaves and lateral branches, senescence of plant parts, and flowering: it also depressed the proportion of stem plus petiole in plant tops and decreased internode elongation, pollen fertility and the number of burrs and seeds formed. As a result of its effect in delaying flowering, copper deficiency would depress seed production particularly strongly when low soil water supply shortens the growing season. The need for suitable procedures for diagnosing copper deficiency is emphasized by the lack of specific plant symptoms in this species.


1975 ◽  
Vol 26 (6) ◽  
pp. 975 ◽  
Author(s):  
RH Groves ◽  
JD Williams

Growth of skeleton weed (Chondrilla juncea, form A) and subterranean clover (Trifolium subterraneum) was studied in a glasshouse experiment in which the species were grown alone or together and the resultant effects of shoot and root competition assessed. The leaf number and weight of plant parts of C. juncea were reduced by competition vith subterranean clover, especially when shoots of the two species were competing. The leaf area of C. juncea was reduced, especially when roots of the two species were growing together. Puccinia chondrillina on C. juncea rosettes reduced leaf number, leaf area, and weight of plant parts. Subterranean clover grown with C. juncea infected with P. chondrillina further reduced the size and weight of the weed. The large reduction in leaf area and root weight of C. juncea (form A) plants in the presence of both subterranean clover and P. chondrillina suggests that growth of this form of C. juncea in Australia will be greatly reduced in pastures containing these species. In the long term, densities of this form may possibly be so lowered that a significant level of control will be reached in a cereal cropping-pasture system.


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