White Clover Stolon Research Articles

Seasonal variation in the vertical distribution of white clover stolons in grazed swards

Abstract Swards under mob stocking or rotational grazing by sheep at Kaikohe, Taupo, Ballantrae, Wairarapa, Palmerston North, Lincoln, and Gore were sampled every three months for three years. The white clover stolon material was dissected into three vertical classes: aerial, surface, and buried. Length and dry weight of stolon in each class were measured. The mean total weight of stolon and the distribution by weight of stolon in the three vertical classes varied among sites (P<0.001). In addition, each year there was a highly significant (P<0.001) seasonal change in the vertical distribution of stolon at each site, with mean levels of approximately 80070 of stolon buried in winter and 40% in summer and autumn. At two sites, Wairarapa and Lincoln, exceptions to the seasonal. pattern of distribution of stolon were observed when low rainfall periods occurred. A significant negative correlation between threemonthly effective rainfall (rainfall minus Penman potential evapotranspiration) and weight per unit l...

Phosphate Uptake and Transport by Roots and Stolons of Intact White Clover (Trifolium repensL.)

Phosphate Uptake and Transport by Roots and Stolons of Intact White Clover (<i>Trifolium repens</i>L.)

Effect of grazing management and season on nitrogen and phosphorus content of leaves and stolons of white clover in mixed swards

Abstract The nitrogen (N) and phosphorus (P) contents of leaf, surface stolon, and buried stolon of white clover (Trifolium repens L.) were measured in samples taken every 2 months, from pasture under rotational grazing by cattle (RGC) and set stocking by sheep (SSS), for 3 years. The effect of the system of grazing management of sheep on N and P content of 3 herbage classes of white clover was examined during a 1-year period by analysing samples taken monthly from pastures with 3 different management backgrounds; set stocked (SS), rotationally grazed (RS) or set stocked from lambing to drafting, then rotationally grazed for the rest of the year (CS). In the 3-year study, the content of N did not differ between the RGC and SSS treatments but the mean values of 4.59% in leaf, 2.75% in surface stolon, and 2.22% in buried stolon all differed. However, P contents differed between treatments: with RGC treatment, mean P levels decreased (0.43, 0.29, and 0.23% for leaf, surface stolon, and buried stolon respecti...

Electrophysiological evidence for the permeability of white clover stolons to nutrient ions

Membrane electrical potential differences (PD) of cells of white clover stolons and roots with secondary thickening have been measured. In dilute nutrient solution the PDs were ca — 154 mV for the 2nd and 10th internodes from the stolon tip and ca — 135 mV for buried internodes and thickened roots. PD between cells along the same radius did not differ consistently. Increasing the potassium concentration of the nutrient solution caused a rapid polarisation of the PD. Phosphate-free media caused the PDs recorded to be less stable and a number of the values to be less polarised. These results suggest that the cuticle and phellem in stolons do not prevent the entry of potassium and phosphate ions.

SEASONAL VARIATION IN THE VERTICAL DISTRIBUTION OF WHITE CLOVER (Trifolium repens L.) STOLONS IN TWO CONTRASTING PASTURES

Swards under rotational grazing by cattle (RGC) and under set stocking by sheep (SSS) were sampled every 2 months for 3 years, and white clover stolon dissected into 3 vertical classes; aerial, surface and buried. Despite large differences in yearly herbage production, sward structure, white clover content, total stolon weight and proportioning of stolon among the vertical classes between the sites, the greatest differences in distribution of stolon among the vertical classes were associated with month of sampling and this was consistent among years at both sites. These results indicate that over a 3-year period, in both swards studied, the white clover component underwent an annual cycle of burial of stolons in winter, re-emergence of growing points in spring and surface stolon development over summer. Keywords: white clover, Trifolium repens, stolons, vertical distribution, seasonal variation.

OBSERVATIONS ON THE DISTRIBUTION OF WHITE CLOYER STOLONS IN HILL SWARDS

Hill swards under mob stocking by sheep at Taupo, Ballantrae and Wairarapa were sampled every three months for one year and white clover stolon dissected into three vertical classes: aerial, surface and buried. In 198081 swards at Ballantrae under three different grazing managements, rotationally grazed by cattle IRGC) and by sheep (RGS) and set stocked by sheep (SSS), were sampled six times over one year and white clover stolon dissected out. The distribution of stolon among the three vertical classes varied with season. Buried stolon ranged from a minimum of 42% in autumn to a maximum of 86% in early spring. The proportion of stolon in the aerial and surface classes peaked in summer at 14% and 48% respectively and was at a minimum in early spring (l%and 13%). Distribution of stolon among the vertical classes differed among sites. The Taupo site had respectively 12% and 17% less stolen buried than the Ballantrae and Wairarapa sites. Environmental conditions such as overgrazing during drought reduced the amount of white clover stolon by up to 70% and modified distribution in favour of the buried class. Grazing management had a large effect both on the amount of stolon in the swerds and on the morphology of stolons. Under RGC there was greater total stolon weight (570 kg/ha) than under RGS (310 kg/ha) and SSS (225 kg/ha). Stolons under RGC were heavier per unit length by 32% and 53% respectively than the stolons under RGS and SSS managements. Keywords: white clover, hill swards,stolons,grazing management, vertical distribution, stolon morphology.

Effect of sheep grazing management on distribution of white clover stolons among 3 horizontal strata in ryegrass/white clover swards

Abstract White clover stolons were dissected from core samples taken from pastures with 3 different management backgrounds; set stocked (S), rotationally grazed (R), or set stocked from lambing until drafting, then rotationally grazed for the rest of the year (C). Stolons were classified as aerial, surface, or buried. Stolon dry weight and stolon length for each stolon class, and the number of growing points were measured once a month for 1 year. Despite causing large differences in pasture availability and structure, sheep grazing management had little effect on the amount of stolon in the sward or the distribution of stolon in the 3 classes. However, management did affect stolon length per unit stolon dry weight and the degree of stolon branching (measured as growing point density) in the order S>C>R. The seasonal change in stolon distribution among the 3 classes was large, but similar for all grazing managements. Aerial and surface stolons were at a maximum in late summer-early autumn and at a minimum ...

Seasonal variation in the distribution of white clover (Trifolium repensL.) stolons among 3 horizontal strata in 2 grazed swards

Abstract White clover stolon material from pasture under rotational grazing by cattle (RGC) and set stocking by sheep (SSS) was dissected into 3 classes: aerial stolon, surface stolon, and buried stolon. The length and dry weight of stolon in each class were measured. Stolon length and weight measurements showed the same trends. The amount of stolon in each class varied markedly with time of sampling and grazing management. The pattern of seasonal change in distribution among the classes was similar for both grazing managements. Aerial stolon peaked in March and then decreased to very low levels in winter and spring. Surface stolon peaked in summer-autumn and was at a minimum in winter and spring. Buried stolon contributed a large proportion of total stolon weight at all times of the year, but varied markedly with season, ranging from a minimum of 30% and 40% in late summer to 87% and 99% in early spring in RGC and SSS swards respectively. There was a sudden decrease by 50% in the size of the buried-stolo...

Anatomy and development of the superficial layers in stolons of white clover (Trifolium repensL.)

Abstract Scanning and transrrussion electron microscopy, together with bright field and fluorescence microscopy, were used to examine the cuticle, epidermis, hypodermis, and cork cambium (phellogen) of white clover (Trifolium repens L.) stolons during growth and maturation. Development of the hypodermis included the deposition of a suberin lamella in the cell walls. No suberin was deposited in the cell walls of the epidermis. The cork cambium was formed in the third to fifth internodes basipetal to the stolon apex, and produced layers of suberised cork cells (phellem) when internodes were 11 to 14 basipetal to the apex. Breakdown of the cuticle began at a very early stage. Bacteria were seen to colonise the cuticle and apparently lyse the cuticle and epidermal cell walls and penetrate eventually into the hypodermis. The suberin lamella appeared to be more resistant to bacterial attack than the cellulose portion of the cell wall. It was concluded that variation in the degree of breakdown of the cuticle was probably responsible for the large variation in phosphate absorption of stolon internodes previously observed.

Phosphate absorption by white clover stolons in pasture

Abstract Uptake of 32p by Trifolium repens L. ‘Grasslands Huia’ stolons from felt pads saturated with labelled P solutiOn was measured in the field. Distribution of activity along sto~ons was heavIly bIased towards the stolon tIp rather than to the basal side of the point of supply, and concentrations of activity were associated with active lateral menstems. ThIS was taken as evidence that white clover could absorb P through its stolons from P solutions over the concentration range 10μM to 1.0 M.

PERFORMANCE OF A HILL COUNTRY WHITE CLOVER SELECTION

A white clover variety selected for New Zealand moist hill country was compared with three other white clover varieties in hill country at Ballantrae. Small plots of the hill country selection, Grasslands Huia, Grasslands Pitau, and the resident Ballantrae white clover were planted into paddocks receiving high or low superphosphate applications and three different managements - rotational grazing by cattle, rotational grazing by sheep, or set-stocked sheep for most of the year. Numbers of white clover stolons, white clover dry matter (DM) and total DM production, and proportion of white clover in cut herbage were determined twice yearly for three years. After one year of grazing the hill country selection consistently had approximately double the stolon numbers of Huia, a significantly higher proportion of clover in the herbage than Huia and clover DM yields 25-63% higher than Huia. These differences were not affected significantly by either management or soil fertility. Pitau and the local Ballantrae white clover were at no time more productive than Huia and frequently were poorer, although stolen numbers of the Ballantrae clover were usually higher during the trial and almost matched the selected variety after three years. The hill country selection is being multiplied for pre-release testing.

Freezing Injury of White Clover Stolons

Freezing Injury of White Clover Stolons

The role of fungi and nematodes as factors associated with death of white clover (Trifolium repens) stolons over summer in south-eastern Queensland

A series of laboratory and field trials examined the role of both fungi and nematodes in causing stolon death of white clover (Trifolium repens) which is typically encountered over summer/early autumn in sub-tropical coastal Queensland. Pythium middletonii was consistently isolated from necrotic stolons and roots of Trifolium spp. collected at a range of sites, and was the only fungal species isolated that was pathogenic to white clover seedlings in glasshouse tests. Under controlled environment conditions P. middletonii also caused a root and stolon rot of mature plants similar to that observed in the field. Preliminary studies suggested that some naturalized white clover strains are more resistant as seedlings than commercial white clover cultivars. In 1974-75 and 1975-76 fungicides were applied at monthly intervals over summer to grazed pastures at two sites. Stolon death was significantly reduced by fungicide at one site in one year. The possible role of plant parasitic nematodes in the decline syndrome was investigated in 1975 at three sites: the decline in clover was significantly reduced by nematicide at each site.