Effects of root temperature on growth of four lines of subterranean clover

1972 ◽  
Vol 23 (1) ◽  
pp. 9 ◽  
Author(s):  
JD Williams

One line of subterranean clover (CPI 14196) produced significantly more dry matter than three other lines (CPI 12621 — Israel, Dwalganup, and Mount Barker) at root temperatures suboptimal for shoot growth (10 and 15°C). These differences were associated with leaf area per plant and the size of individual leaves, and the greater growth was associated with partitioning of a greater part of the dry matter to leaves. The significance of the results is discussed in terms of limits to winter production of pastures based on subterranean clover.

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.


1992 ◽  
Vol 43 (3) ◽  
pp. 717
Author(s):  
RC Rossiter

Two experiments were conducted in an open-sided glass shelter at Perth during winter. Subterranean clover (Trifolium subterraneum, L.) seedlings were grown in shallow seed boxes at low plant densities, 2 4 and 2 0 plants/dm2. The effects of a single defoliation involving mainly the removal of cotyledons only, on shoot growth and leaf production were measured at harvest, c. 5 weeks after sowing. Total shoot dry weights were reduced by 15-30% when 40-60% of the leaf area was removed by single defoliations from days 7 to 19 after planting. However, the growth was reduced by almost 70% when both cotyledons were removed (days 7 to 9) before emergence of the unifoliate leaf, i.e. when all of the leaf area was removed. In general, the relative reduction in growth largely depended on the percentage of leaf area removed, rather than on time of removal. Defoliation also reduced the size of trifoliate leaves, and total numbers of trifoliate leaves at harvest. There was a linear relationship between total leaf numbers and shoot dry weights. In the field, these findings are probably of more relevance in terms of insect damage, especially from redlegged earth mites, than for grazing by sheep.


1958 ◽  
Vol 9 (1) ◽  
pp. 53 ◽  
Author(s):  
JL Davidson ◽  
CM Donald

An experiment was conducted to study the growth of subterranean clover (Trifolium subterraneum L.) sown at different densities; the control swards were not defoliated while others were subjected to a single defoliation at various dates. During the final month the rate of dry matter production (tops only) increased to a maximum when the leaf area index (the ratio of the area of the leaves to the area of the ground surface — L.A.I.) was about 4-5, falling by about 30 per cent. as the L.A.I. increased to 8.7. The rate of leaf production was greatest at about L.A.I. 4-5, falling to zero at L.A.I. 8.7. Climatic conditions during the growing season influenced the relationship of L.A.I. to growth; as conditions became more favorable the values of the optimum LA.1. for growth and of the ceiling L.,4.1. progressively rose. Irrespective of the density, all swards tended towards a common ceiling L.A.I. and yield by the end of the season. The effect of defoliation depended on the L.A.I. at which defoliation occurred, on the value to which the L.A.I. was reduced, and on current climatic conditions. If swards near the ceiling L.A.I. were defoliated, total dry matter production was slightly increased and there was a great increase in leaf production. On the other hand, defoliation of swards from about the optimum L.A.I. to very low L.A.I. values led to a substantial reduction in both dry matter and leaf production. It is suggested that all these effects depend on the light relationships within the sward and their influence on the balance of photosynthesis and respiration. Pasture at the optimum L.A.I. will give greater production than swards of lower or higher L.A.I.; defoliation can give greatly increased leaf production, unless L.A.I. is reduced to very low values.


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.


1991 ◽  
Vol 116 (2) ◽  
pp. 201-205 ◽  
Author(s):  
Frank Kappel

The effect of fruit on shoot growth, leaf area, and on dry weight (DW) partitioning into leaves, fruit, trunk, and branch sections was investigated using 7-year-old `Lambert' sweet cherry (Prunus avium L.) trees. Dormant trees were sampled in the spring, and fruiting and deblossomed trees were sampled and compared at fruit harvest and just before leaf fall. Fruiting reduced shoot growth, leaf area, and above-ground DW accumulation of the trees. The annual above-ground DW accumulated was 13.4 kg for fruiting trees and 16.0 kg for nonfruiting trees. The greatest proportion of above-ground DW was partitioned to wood, whereas the least was partitioned to fruit. Current-season's growth (wood and leaves) appears to be a greater sink for photosynthates than is fruit because a greater proportion of above-ground DW was partitioned to current-season's growth than to fruit.


2015 ◽  
Vol 45 (11) ◽  
pp. 1917-1924
Author(s):  
Dilson Antônio Bisognin ◽  
Jacso Dellai

The aim of this research was to determine the effect of shoot growth restriction in the dry matter partitioning and minituber production of potato plants grown in a closed soilless system. Minitubers of the cultivars 'Macaca' and 'Asterix' were planted in the greenhouse in the density of 100 hills m-2, during autumn and spring growing seasons. Growth restriction levels were gotten by pruning shoots at 10, 20 and 30cm height or without pruning. The growth restriction levels were identified by their respective leaf area index. The experiment was a factorial (cultivars x growth restriction x growing season) in a random design, with four replications. Growth restriction affected the dry matter production of potato plants in both growing seasons and cultivars. Pruning potato plants at 30cm is a feasible technique to control leaf area index and it has lower effect on harvest index and number than in dry matter production of minitubers. Growth restriction does not change dry matter partitioning of potato plants grown in soilless system.


Helia ◽  
2001 ◽  
Vol 24 (35) ◽  
pp. 135-148
Author(s):  
Mohammed El Midaoui ◽  
Ahmed Talouizte ◽  
Benbella Mohamed ◽  
Serieys Hervé ◽  
Ait Houssa Abdelhadi ◽  
...  

SUMMARYAn experiment has been carried out in order to study the behaviour under mineral deficiency of three sunflower genotypes, a population variety (Oro 9) and two hybrids (Mirasol and Albena). Sunflower seedlings were submitted to five treatments: N deficiency (N0), P deficiency (P0), K deficiency (K0), N and K deficiency (N0K0) and a control. Plants were harvested when they reached 3-4 true pairs of leaves. Growth parameters measured (height, total leaf area, root length, root and shoot dry mater) were all significantly reduced by mineral deficiency. Leaf area was most reduced by N0 (-61%) and P0 (-56%). Total dry matter was most affected by N0 (-63%) and by N0K0 (-66%). Genotype comparisons showed that Oro 9 had the highest shoot dry matter while Albena had the lowest root dry matter. Effect of mineral deficiency on content and partitioning of N, P, K, Ca and Na was significant and varied according to treatments and among plant parts. Shoot dry weight was significantly correlated with root N content (r2=0.81) and root K content (r2=-0.61) for N0 and K0.


Author(s):  
Muhammad Zeeshan Mehmood ◽  
Ghulam Qadir ◽  
Obaid Afzal ◽  
Atta Mohi Ud Din ◽  
Muhammad Ali Raza ◽  
...  

AbstractSeveral biotic and abiotic stresses significantly decrease the biomass accumulation and seed yield of sesame crops under rainfed areas. However, plant growth regulators (such as Paclobutrazol) can improve the total dry matter and seed production of the sesame crop. The effects of the paclobutrazol application on dry matter accumulation and seed yield had not been studied before in sesame under rainfed conditions. Therefore, a two-year field study during 2018 and 2019 was conducted with key objectives to assess the impacts of paclobutrazol on leaf greenness, leaf area, total dry matter production and partitioning, seed shattering, and seed yield of sesame. Two sesame cultivars (TS-5 and TS-3) were treated with four paclobutrazol concentrations (P0 = Control, P1 = 100 mg L−1, P2 = 200 mg L−1, P3 = 300 mg L−1). The experiment was executed in RCBD-factorial design with three replications. Compared with P0, treatment P3 improved the leaf greenness of sesame by 17%, 38%, and 60% at 45, 85, and 125 days after sowing, respectively. However, P3 treatment decreased the leaf area of sesame by 14% and 20% at 45 and 85 days after sowing than P0, respectively. Compared with P0, treatment P3 increased the leaf area by 46% at 125 days after sowing. On average, treatment P3 also improved the total biomass production by 21% and partitioning in roots, stems, leaves, capsules, and seeds by 23%, 19%, 23%, 22%, and 40%, respectively, in the whole growing seasons as compared to P0. Moreover, under P3 treatment, sesame attained the highest seed yield and lowest seed shattering by 27% and 30%, respectively, compared to P0. This study indicated that by applying the paclobutrazol concentration at the rate of 300 mg L−1 in sesame, the leaf greenness, leaf areas, biomass accumulation, partitioning, seed yield, and shatter resistance could be improved. Thus, the optimum paclobutrazol level could enhance the dry matter accumulation and seed production capacity of sesame by decreasing shattering losses under rainfed conditions.


Sign in / Sign up

Export Citation Format

Share Document