Zinc in subterranean clover (Trifolium subterraneum L. cv. Seaton Park). I. Effects of zinc supply on distribution of zinc and dry weight among plant parts

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.


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.



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.



1958 ◽  
Vol 9 (1) ◽  
pp. 73 ◽  
Author(s):  
DS Riceman ◽  
GB Jones

The distribution of dry weight and of zinc and copper at different stages of growth has been examined in Trifolium subterraneum L. var. Bacchus Marsh grown in culture solutions to which graduated amounts of zinc were added. Several characteristics of the growth of the plants were assessed quantitatively. Symptoms of zinc deficiency developed in cultures which were supplied with suboptimal amounts of zinc.



1954 ◽  
Vol 5 (3) ◽  
pp. 356 ◽  
Author(s):  
WM Hutton ◽  
JW Peak

Induced autotetraploidy in the Dwalganup variety of subterranean clover (Trifolium subterraneum L.) resulted in total dry weight increases of 60 and 65.5 per cent. at flowering and maturity respectively. In the other four varieties the tetraploids had decreased yields of dry matter compared with the diploids, although the decreases for leaf weights at flowering were nonsignificant in Mount Barker and Tallarook, as was the total dry weight reduction in Tallarook at maturity. There were no significant differences between the diploids and tetraploids in percentage moisture content. When early development was stimulated by growth in a glass-house, the tetraploids of all varieties showed a significant increase in yield of green matter. The level of increased growth was maintained only in Dwalganup, and decreased in other varieties during flowering. An analysis was made of the way in which the different plant parts mere changed by tetraploidy. Where decreased growth occurred, the leaves and stems were coarser. In all varieties a reduced seed-setting followed autotetraploidy, although in Dwalganup the yield of seed per plant was not affected.



1976 ◽  
Vol 27 (5) ◽  
pp. 593 ◽  
Author(s):  
EAN Greenwood ◽  
BA Carbon ◽  
RC Rossiter ◽  
JD Beresford

The objective was to characterize the response of Trifolium subterraneum L. (cv. Daliak) swards to short-term and to long-term changes in temperature at several stages of plant growth. Short-term responses were studied with microswards growing in boxes in the open and defoliated every week to simulate heavy grazing. At seven stages, one subsample of boxes was harvested and three other subsamples were moved to controlled-temperature glasshouses and grown for 14 days at 10/5° (day/night), 17.5/12.5° and 25/20°C respectively, and then harvested. Dry weights and numbers of plant parts, and areas of leaves, height, light penetration and net carbon dioxide exchange of swards were measured. For long-term responses, young, defoliated microswards were transferred to the above temperatures for 9 weeks and cut weekly. On days 32 (pre-treatment harvest), 53, 74 and 95, tops and roots were harvested. The results support three generalizations. Firstly, severely defoliated subterranean clover pastures respond to temperature between 10/5° and 25/20° in a variety of ways over the whole life cycle. However, temperature is of greater importance as a determinant of dry weight of tops during the post-emergence and reproductive phases than it is during the preflowering phase. Secondly, total growth rate (TGR) after the first 8–10 weeks of growth does not increase at temperatures above 10/5°. And thirdly, even with moderately low LAI values of 1–4, temperatures of 25/20° can inhibit TGR after about 8 weeks of growth. The biological and agricultural implications are discussed.



1956 ◽  
Vol 7 (6) ◽  
pp. 495 ◽  
Author(s):  
DS Riceman ◽  
GB Jones

Changes in the distribution of zinc, copper, and dry matter in seedlings of Trifolium subterraneum L. var. Bacchus Marsh grown in solution cultures which were supplied with copper but not with zinc have been traced during the first 40 days after germination. Increase in total dry weight was accompanied by a rapid decline in the concentration of zinc in the plant parts examined. Symptoms of zinc deficiency were recognizable in the third trifoliate leaf by the time the leaflets opened, 33 days after germination. At that time the concentration of zinc in leaf plus petiole had fallen to 14 p.p.m. in the dry matter. There was a continual net loss of zinc from the cotyledons. A marked increase in the amount of copper present in roots, and in leaf plus petiole, occurred soon after the addition of copper to the cultures 20 days after germination, but no substantial change was observed in the amount of copper present in the cotyledons or in the hypocotyl plus growing point. These latter tissues had previously lost small amounts of copper.



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.



1955 ◽  
Vol 8 (3) ◽  
pp. 344 ◽  
Author(s):  
PG Ozanne

The effects of light on zinc response were investigated by growing subtermnean clover under daylight of various intensities. Plants were grown in limed Muchea sand and the zinc response was measured as the difference in dry weight between plants with and without added zinc. The light intensities are given as the mean daily maximum intensities.



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.



1963 ◽  
Vol 14 (2) ◽  
pp. 206 ◽  
Author(s):  
JN Black

This paper describes two experiments analysing the recovery from defoliation of subterranean clover varieties grown in swards in large seed boxes at the Waite Agricultural Research Institute, Adelaide. The first experiment examined the way in which the six common commercial varieties recovered from a single severe defoliation, and showed that under these conditions they can be placed in three groups: Yarloop and Clare are tall, high-yielding varieties with few, large leaves, recovering slowly from defoliation; Tallarook and Dwalganup are prostrate varieties, lower-yielding, with many small leaves, recovering rapidly after defoliation; Bacchus Marsh and Mount Barker are intermediate in all respects. In the second experiment mixed swards of equal numbers of Yarloop and Tallarook plants were grown under three treatments: A, no defoliation; B, defoliated twice at a height which removed the higher Yarloop canopy but left the lower Tallarook plants untouched; C, defoliated twice at a height which removed the canopies of both varieties. Measurement of dry weight on four occasions after each defoliation showed that in the undefoliated treatment, all Tallarook plants died by the end of the experiment. In the defoliated treatments, the removal of the Yarloop canopy resulted in only a temporary improvement in the illuniination in which the Tallarook plants grew, and their dry weight and plant numbers progressively declined. Dry weight changes in the Tallarook component were shown to be dependent on the light energy available to it, which was in turn determined by the light-absorbing capacity of the superior Yarloop canopy. In mixed swards, the ability of Yarloop to re-establish quickly a leaf canopy above that of Tallarook appeared to explain its success when defoliated.



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