Growth of skeleton weed (Chondrilla juncea L.) as affected by growth of subterranean clover (Trifolium subterraneum L.) and infection by Puccinea chondrillina Bubak and Syd

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.

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 (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.


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.


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. 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.


1957 ◽  
Vol 8 (4) ◽  
pp. 335 ◽  
Author(s):  
JN Black

The significance of seed weight in the growth of subterranean clover (Trifolium subterraneum L) , of the Bacchus Marsh strain, has been assessed under both spaced plant and sward conditions at the Waite Agricultural Research Institute. Under conditions of spacing, plants of three widely separated seed size grades were grown a t a density of 1 per 25 sq. links. The dry weights of the plants were proportional to seed weight from the time of sowing (in May) till the end of October – over almost the entire growing period of the crop. Three sets of swards were grown a t a density of 25 plants per sq. link, each sward being planted with seed of one of the three sizes. Dry weight was proportional to seed weight in the early part of the season but when the swards reached a leaf area index of about 4 (i.e. when there were 4 sq. links of leaf surface on 1 sq. link of ground), a reduction in growth rate occurred. This critical leaf area index was reached first in "large seed" swards, followed later by "medium seed" and finally by "small seed" swards. Thus there was a period in which the swards were growing at different rates, and in which the dry weights came to parity, so that on the final sampling occasion (in December) there was no significant difference between the dry weights of the swards from the three seed sizes. It is concluded that a t a leaf area index of about 4, interception of incident light energy is complete.


2018 ◽  
Vol 14 (1) ◽  
pp. 14-20
Author(s):  
Yance N Ayal ◽  
Henry Kesaulya ◽  
Francina Matulessy

This research was aimed to get the optimum NPK fertilizer dosage with the time of liquid organic fertilizer application to support the growth and yield of pakcoy (Brassica rappa L.). The study used a Randomized Block Design with three replications. Observation variables included plant height, leaf number, leaf area, total plant weight, root length, root weight and total plant weight percentage. The results showed that N0 (without NPK fertilizer) was the best based on the plant height and leaf number. Liquid organic fertilizer given at 3-time applications per plant (W3) contributed significantly to leaf number at 35 days after planting and gave the highest yield of leaves, with 17,45 leaves. The treatment of NPK compound fertilizer dosage with the time of liquid organic fertilizer gave significant effects on the leaf area, total plant weight, root length, and root weight. Keywords: liquid organic fertilizer, NPK, pakcoy   ABSTRAK Penelitian ini bertujuan untuk mendapatkan dosis pupuk NPK dengan waktu plikasi pupuk organik cair yang tepat untuk menunjang pertumbuhan danp roduksi tanaman pakcoy (Brassica rappa L.). Penelitian mengunakan Rancangan Acak Kelompok dengan tiga ulangan. Peubah-peubah pengamatan meliputi tinggi tanaman, jumlah daun, luas daun, berat total tanaman, panjang akar, berat akar dan persentase berat total tanaman. Hasil penelitian menunjukkan bahwa perlakuan N0 (tanpa pupuk NPK) merupakan yang terbaik dari penelitian ini terhadap parameter tinggi tanaman dan jumlah daun. Waktu pemberian pupuk organik cair 3 kali/tanaman (perlakuan W3) memberikan kontribusi yang signifikan terhadap jumlah daun 35 hari setelah tanam dan menghasilkan daun terbanyak dengan jumlah 17,45 helai. Perlakuan dosis pupuk majemuk NPK dengan waktu pemberian pupuk organik cair memberikan pengaruh yang nyata sampai sangat nyata terhadap luas daun, berat total tanaman, panjang akar serta berat akar. Kata kunci: NPK, pakcoy, pupuk organik cair


HortScience ◽  
2010 ◽  
Vol 45 (5) ◽  
pp. 771-774 ◽  
Author(s):  
Youbin Zheng ◽  
Linping Wang ◽  
Diane Feliciano Cayanan ◽  
Mike Dixon

To determine the nutrient solution copper (Cu2+) level above which Cucumis sativus L. (cucumber, cv. LOGICA F1) plant growth and fruit yield will be negatively affected, plants were grown on rockwool and irrigated with nutrient solutions containing Cu2+ at 0.05, 0.55, 1.05, 1.55, and 2.05 mg·L−1. Copper treatment began when plants were 4 weeks old and lasted for 10 weeks. During this 10-week period, plants were harvested at 3 weeks (short-term) and 10 weeks (long-term) after the start of Cu2+ treatment. Neither visible leaf injury nor negative Cu2+ effect was observed on plant growth (leaf number, leaf area, leaf dry weight, and stem dry weight) after 3 weeks of continuous Cu2+ treatment. However, after 10 weeks of continuous Cu2+ application, cucumber leaf dry weight was significantly reduced by Cu2+ levels 1.05 mg·L−1 or greater; leaf number, leaf area, and stem dry weight were significantly reduced by Cu2+ levels 1.55 mg·L−1 or greater. Copper (Cu2+ levels 1.05 mg·L−1 or greater) also caused root browning. Some plants under the 2.05 mg·L−1 Cu2+ treatment started to wilt after 6 weeks of continuous Cu2+ treatment. Copper treatment did not result in any change in leaf greenness until after Week 9 from the start of the treatments. There was no sign of a negative Cu2+ effect on cucumber fruit numbers after the first 2 weeks of production, but plants under the highest Cu2+ concentration treatment (2.05 mg·L−1) gradually produced fewer cucumber fruit than the control (0.05 mg·L−1) and eventually resulted in lower cucumber yield. Nutrient solution can be treated with 1.05 mg·L−1 of Cu2+ in cucumber production greenhouses; however, it is not recommended to use Cu2+ concentrations 1.05 mg·L−1 or greater continuously long-term (more than 3 weeks). When applying Cu2+, it is suggested that cucumber roots be examined regularly because roots are a better indicator for Cu2+ toxicity than leaf injury.


1970 ◽  
Vol 5 (1) ◽  
Author(s):  
Lia Karlina Br Sembiring ◽  
Rosita Sipayung ◽  
Irsal

Massive breeding is often the case with the availability of the amount of water that can be stored on the media. The aim of this research is to know the influence of media and the frequency of watering on the growth of robusta coffee seedlings and to find the best media and optimum watering frequency. This experiment was conducted at the Faculty of Agriculture, University of Sumatera Utara, Medan from June to September 2017. The experimental method used was Factorial Randomized Block Design with 2 treatment factors, ie 1: planting medium ie, topsoil ; topsoil: sand (2: 1); topsoil: rice husk (2: 1), topsoil: charcoal husk (2: 1) and factor 2: watering frequency ie, watered once a day; watered every 4 days; watered 7 days and watered once every 10 days. The variable was plant height, stem diameter, total leaf number, total leaf area, fresh crown weight, canopy dry weight, fresh root weight, root dry weight, longest root, and canopy and root ratio. The results showed that planting media treatment had a significant effect on plant height variables, stem diameter increase, leaf number, total leaf area, fresh crown weight, canopy dry weight, fresh root weight, root dry weight, and root canopy ratio. The best treatment of planting medium was found in topsoil treatment: rice husk (2: 1). The treatment of watering frequency had a significant effect on the stem diameter 2 - 12 of the week after planting move observation variable, total leaf area, fresh crown weight, dry crown weight, fresh root weight, and dry weight of roots. The best treatment frequency of watering hose is watering every 4 days. The interaction between the two treatments had a significant effect on the diameter of the stem diameter variable, the total leaf area and the fresh weight of the canopy.


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