scholarly journals Effects of stage of defoliation on seed production and growth of Stylosanthes humilis

1970 ◽  
Vol 10 (46) ◽  
pp. 577 ◽  
Author(s):  
DS Loch ◽  
LR Humphreys

Stylosanthes humilis swards grown at Brisbane in irrigated boxes were defoliated (about 60 per cent removal of tops) at floral initiation, first flower appearance, or advanced flowering stages ; seed yield was 45, 16, and 14 per cent respectively of seed yield in undefoliated swards. Decreased yields were primarily due to poor seed set of florets, were also associated with reduced inflorescence density and floret number per inflorescence, and occurred despite increases (in some defoliation treatments) in seed size, leaf growth rate, and differentiation of leaves and branches. Total seasonal plant growth was independent of defoliation treatment.

1973 ◽  
Vol 81 (2) ◽  
pp. 219-229 ◽  
Author(s):  
P. A. Chadhokar ◽  
L. R. Humphreys

SummaryPaspalum plicatulum was grown at Brisbane in boxes of sand receiving basal nutrients and frequent irrigation; weekly levels of ammonium nitrate application were varied according to growth and development stage.The rate of tiller appearance increased to a maximum 40–50 days after sowing and almost ceased thereafter. Tiller leaf number, survival, fertility, inflorescence branching, seeds per raceme and seed size were positively related to tiller age. Young tillers were more sensitive to variations in nitrogen supply than old tillers.Adequate nitrogen nutrition during the vegetative phase from sowing to floral initiation (93 days) increased tiller and hence inflorescence density; increased inflorescence branching was compensated by fewer seeds per raceme. Good nitrogen nutrition during the phase from floral initiation to inflorescence exsertion (142 days) increased survival of late-formed tillers and hence inflorescence density; inflorescence branching, seeds per raceme and seed size were also increased. Nitrogen stress during the final maturation phase did not affect seed yield.


1987 ◽  
Vol 38 (5) ◽  
pp. 869
Author(s):  
WW Stnr ◽  
LR Humphreys

Long-established swards of Brachiaria decumbens cv. Basilisk and of Paspalum plicatulum cv. Rodds Bay at Mt Cotton, south-east Queensland, were cut, field dried and burnt, or cut and the residues removed in late November or early January. Burning initially reduced tillering, especially when the interval between cutting and burning was 7 days, but this difference disappeared in P. plicatulum when there was a long interval to floral initiation. A juvenility requirement was evident in the short day P. plicatulum swards, where late burning or cutting delayed floral initiation 11 days relative to early defoliation. Strong compensatory and hierarchical effects on the components of seed yield occurred, and seed yield was similar in cut or burnt treatments, except for 23% decrease in late cut P. plicatulum. Late defoliated B. decumbens yielded 31% more seed than early defoliated swards, due mainly to reduced spikelet number per raceme (branch). Burning slightly increased synchrony of inflorescence exsertion in P. plicatulum and reduced crop lodging, although in a subordinate experiment with P. plicatulum lodging was positively related to level of nitrogen supply rather than to defoliation treatment.


2015 ◽  
Vol 63 (8) ◽  
pp. 705 ◽  
Author(s):  
Rina Aleman ◽  
Manfred Jusaitis ◽  
Joan Gibbs ◽  
Phillip Ainsley ◽  
Fleur Tiver ◽  
...  

Brachyscome ciliaris is a floriferous Australian native daisy, with potential for use as a horticultural species. The species is hardy and seeds are relatively easy to germinate, but it is unique within the Brachyscome genus in that seeds are distinctly dimorphic. Within a fruiting capitulum, ray seeds are smooth and narrow with a minute pappus, whereas disc seeds have broad flat wings with curled hairs and a longer pappus than that of ray seeds. Both seed morphs, collected from five populations of the species, were tested to determine differences in their morphology, germination speed and percentage, seedling growth and wind-dispersal characteristics. Ray seeds were generally lighter and smaller than disc seeds and their length varied significantly with provenance. Dormancy levels of the two seed morphs and growth of ray- and disc-derived seedlings did not differ significantly, but differences were significant among the five populations tested. Seeds germinated readily, and germination was optimal under winter or summer conditions and lower in spring or autumn. Seed production by plants raised from ray or disc seeds was identical, but Noora-sourced plants yielded more seed than did plants sourced from the other provenances tested. Seed size, germination and plant growth of B. ciliaris varied significantly among populations. Winged disc seeds were dispersed slightly further by wind than were wingless ray seeds. We concluded that dormancy, germination and seed-yield characteristics of B. ciliaris were all influenced more by seed provenance than by seed morph (ray or disc).


1971 ◽  
Vol 76 (3) ◽  
pp. 325-328 ◽  
Author(s):  
H. M. Shelton ◽  
L. R. Humphreys

SUMMARYStylosanthes humilis was grown at Brisbane at densities of 10, 50, 250, 850 and 3800 plants/m2 in boxes of sand which received basal nutrients, applications of 0, 10 and 50 kg P/ha as calcium dihydrogen phosphate, and frequent irrigation.Maximum seed yield was 69 g/m2 at a density of 850 plants/m2. Seed yield was linearly related to the logarithm of density up to 250 plants/m2, and was comparatively stable over the upper density range, declining slightly at supra-optimal density. Inflorescence density exerted the primary control over seed yield, but seed set per floret and floret number per inflorescence were also influential.The application of 50 kg P/ha increased yield of plant tops by 54% and seed yield by 20%.


1967 ◽  
Vol 47 (5) ◽  
pp. 577-583 ◽  
Author(s):  
A. Johnston ◽  
M. D. MacDonald

Three thousand seven hundred and eighty shoot apices of Festuca scabrella Torr. were examined over a three-year period. Stages of development and height of apices above the root-stem transition were recorded. Initiation and partial floral development occurred in autumn, 1963 and 1965; seed set in native stands was good in 1964 and 1966. Initiation failed to occur in 1964 and 1966; seed set was poor in 1965 and a poor seed crop in 1967 appeared likely. Causes of induction and later initiation of floral development were not determined. The tendency of F. scabrella to decrease in abundance when grazed heavily was attributed to its erect growth habit and lack of lateral tillers rather than to factors associated with the developmental morphology of the shoot apex.


2006 ◽  
Vol 57 (4) ◽  
pp. 427 ◽  
Author(s):  
R. Shrestha ◽  
N.C. Turner ◽  
K. H. M. Siddique ◽  
D. W. Turner ◽  
J. Speijers

An experiment was conducted under controlled conditions in a glasshouse to determine the sensitivity of reproductive development of lentil (Lens culinaris Medikus) genotypes of different origins to water deficit. The 3 genotypes were Cassab (West Asia), Simal (South Asia), and ILL 7979 a crossbred between a West Asian genotype and a South Asian genotype. Two watering treatments, a well-watered control and a water-deficit treatment, were imposed from the beginning of podding. Leaf water relations, total dry matter production, leaf area, and number of flowers, pods, and seeds were measured from podding to maturity. In the well-watered plants the leaf water potential (ψleaf) before sunrise ranged from −0.6 to −0.8 MPa. When subjected to water deficit, ψleaf fell to about −3.0 MPa. Genotypes did not show variation in vegetative growth or seed yield under either well-watered or water-deficit conditions, but they differed significantly in the number of flowers, fruiting nodes, pods, and seeds, and harvest index (HI). Seed size in Cassab was 61% larger than ILL 7979 and 105% larger than Simal. The small-seeded genotypes produced the highest number of fruiting nodes and hence a greater number of flowers, pods, and seeds. Seed size was positively correlated with seed growth rate (r = 0.77**) and seed fill duration (r = 0.45*). The water deficit reduced plant height by about 20%, leaf area by 48–81%, and total dry matter by about 60% compared with well-watered plants. The water deficit reduced flower number by 35–46% and increased seed abortion (empty pods) by 17–46%. The water deficit had no effect on the maximum seed growth rate, seed fill duration, or final seed size in any of the 3 genotypes. Therefore, the 70% reduction in seed yield induced by the water deficit was primarily due to a reduction in pod and seed numbers (by 59–70%) rather than individual seed growth rate and seed size.


2018 ◽  
Vol 8 (1) ◽  
Author(s):  
E. Hanggari Sittadewi., dkk

Nutrient Block is a growing medium product in the form of a square (25 x 25 cm) or cylindrical (diameter = 20 cm, height = 25 cm) made of peat which has been composted, plus adhesive gypsum or tapioca waste. Nutrient Block is designed to support the post mining land rehabilitation program that is now threatening the environmental degradation in mining areas. Nutrient Block products has been proved good for growth because of the media in addition to having physical properties that are capable of storing large amounts of water, contain enough nutrients in the form available to plants,so it can support plant growth. Results of the Nutrient Block application test to Jabon (Anthocephalus cadaba) and Sengon (Paraserianthes falcataria) plants showed that good performance, both plant height and diameter of trees and leaf growth in plants Jabon appear healthy and getting wider.keywords: nutrient block, post-mining land rehabilitation. Paraserianthes falcataria, Anthocephalus cadaba


2021 ◽  
Vol 13 (6) ◽  
pp. 3569
Author(s):  
Hua Cheng ◽  
Baocheng Jin ◽  
Kai Luo ◽  
Jiuying Pei ◽  
Xueli Zhang ◽  
...  

Quantitatively estimating the grazing intensity (GI) effects on vegetation in semiarid hilly grassland of the Loess Plateau can help to develop safe utilization levels for natural grasslands, which is a necessity of maintaining livestock production and sustainable development of grasslands. Normalized difference vegetation index (NDVI), field vegetation data, and 181 days (one goat per day) of GPS tracking were combined to quantify the spatial pattern of GI, and its effects on the vegetation community structure. The spatial distribution of GI was uneven, with a mean value of 0.50 goats/ha, and 95% of the study area had less than 1.30 goats/ha. The areas with utilization rates of rangeland (July) lower than 45% and 20% made up about 95% and 60% of the study area, respectively. Grazing significantly reduced monthly aboveground biomass, but the grazing effects on plant growth rate were complex across the different plant growth stages. Grazing impaired plant growth in general, but the intermediate GI appeared to facilitate plant growth rate at the end of the growing seasons. Grazing had minimal relationship with vegetation community structure characteristics, though Importance Value of forbs increased with increasing GI. Flexibility in the number of goats and conservatively defining utilization rate, according to the inter-annual variation of utilization biomass, would be beneficial to achieve ecologically healthy and economically sustainable GI.


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