White clover sensitivity to UV-B radiation - biochemical relationships and interaction with drought

2003 ◽  
pp. 273-277
Author(s):  
R.W. Hofmann ◽  
B.D. Campbell ◽  
E.E. Swinny ◽  
S.J. Bloor ◽  
K.R. Markham ◽  
...  
Keyword(s):  
New Zealand ◽  
White Clover ◽  
Ultraviolet B ◽  
Summer Drought ◽  
Stress Protection ◽  
Trade Offs ◽  
Population Comparisons ◽  
Potential Benefits ◽  
Quercetin Glycosides ◽  
Balance Trade

During summertime in New Zealand, white clover experiences high levels of ultraviolet-B (UV-B) radiation. This frequently coincides with periods of summer drought. We investigated responses to UV-B and to the combination of UV-B and drought in various white clover populations, including New Zealand cultivars and ecotypes as well as overseas germplasm. The results were obtained under controlled environmental conditions in three independent trials. Overall, white clover growth was reduced by UV-B. The population comparisons indicated that low growth rate and adaptation to other forms of stress may be related to UV-B tolerance under well-watered conditions, but not during extended periods of drought. Flavonoid pigments that are involved in stress protection were strongly increased under UV-B and were further enhanced in the combination of UV-B and drought. The responses among these flavonoids were highly specific, with more pronounced UV-B-induced increases in quercetin glycosides, compared to their closely related kaempferol counterparts. UV-B toler ance of the less productive white clover populations was linked to the accumulation of quercetin compounds. In conclusion, these studies suggest (i) that slow-growing white clover ecotypes adapted to other stresses have higher capacity for biochemical acclimation to UV-B under well-watered conditions and (ii) that these biochemical attributes may also contribute to decreased UV-B sensitivity across white clover populations under drought. The findings alert plant breeders to potential benefits of selecting productive germplasm for high levels of specific flavonoids to balance trade-offs between plant productivity and stress tolerance. Keywords: Drought, flavonoids, genetic variation, HPLC, kaempferol, quercetin, str ess, Trifolium repens L., ultraviolet-B, white clover

scholarly journals A COMPARISON OF RYEGRASS CULTIVARS IN SOUTH CANTERBURY 1. Perennial cultivars

1973 ◽  
pp. 211-218
Author(s):  
C.C. Mcleod
Keyword(s):  
New Zealand ◽  
Drought Resistance ◽  
White Clover ◽  
Annual Production ◽  
Summer Drought ◽  
Total Production

The seasonal and annual production of New Zealand perennial ryegrasses were compared with that of a number of overseas cultivars. Several imported tetraploids established much more quickly than the New Zealand standards. R.V.P. Melle, Barlatra, S23 and New Zealand Mangere showed good summer drought resistance. At Waimate Mangere gave the h,ighest seasonal and total production while at Timaru, where Mangere was not included, Grasslands Ruanui and Grasslands Ariki gave the highest autumn, spring and total yields. White clover was usually higher yielding when with the less productive ryegrasses. This often meanst that ryegrass plus clover yield differences were less than those of the ryegrass cultivars alone.

EVALUATION OF NEW ZEALAND BRED WHITE CLOVER CULTIVARS UNDER ROTATIONAL GRAZING AND SET STOCKING WITH SHEEP

1988 ◽  
pp. 203-206 ◽  
Author(s):  
J.L. Brock
Keyword(s):  
New Zealand ◽  
White Clover ◽  
Large Scale ◽  
Moisture Stress ◽  
Early Summer ◽  
Summer Drought ◽  
Stocking Rate ◽  
Rotational Grazing ◽  
Second Year ◽  
Clover Content

The four New Zealand bred white clover cultivars. Tahora, Hula, Pltau and Kopu were evaluated for two years under a high stocking rate in self contained sheep grazed farmlets comparing year round rotational grazing with set stocking. Tahora was clearly superior under set stocking, yielding 50% more than Huia and 140% more than Pitau and Kopu. Under rotational grazing all performed well with only Kopu showing a 20% advantage. An unseasonal early summer drought in the second year showed all cultivars to be highly susceptible to moisture stress at this time under rotational grazing. Large scale death of clover occurred reducing clover content to 2-3% in autumn with no recovery by mid winter. Under set stocking, although severely wilted, all clovers quickly recovered to their former level following rain The management implications are discussed. Keywords: Tahora. Huia, Pitau, Kopu, grazing management, drought, cultivar choice

THE PERFORMANCE OF S170 TALL FESCUE IN CANTERBURY

1974 ◽  
pp. 214-215
Author(s):  
B.R. Watkin
Keyword(s):  
New Zealand ◽  
White Clover ◽  
Tall Fescue ◽  
Trifolium Repens ◽  
Festuca Arundinacea ◽  
Sheep Grazing ◽  
Selection Of

AN Aberystwyth selection of tall fescue (Festuca arundinacea Schreb.), known as S170, was sown with certified New Zealand white clover (Trifolium repens) and re' clover (T. pratense) and compared under sheep grazing with other grass/clover pastures at the Grasslands Division Regional Station at Lincoln (Watkin, 1975) .

EVALUATION OF CLOVERS ON SANDY COASTAL SOIL

1977 ◽  
pp. 130-138 ◽  
Author(s):  
W.M. Williams ◽  
L.B. Anderson ◽  
B.M. Cooper
Keyword(s):  
New Zealand ◽  
Drought Stress ◽  
Sandy Soil ◽  
White Clover ◽  
Plant Material ◽  
Red Clover ◽  
Early Spring ◽  
Commercial Cultivars ◽  
Mediterranean Origin ◽  
Winter Annual

In evaluations of clover performances on summer-dry Himatangi sandy soil, it was found that none could match lucerne over summer. Emphasis was therefore placed on production in autumn-winter- early spring when lucerne growth was slow. Evaluations of some winter annual clover species suggested that Trifolium spumosum, T. pallidum, T. resupinatum, and T. vesiculosum would justify further investigation, along with T. subterraneum which is already used in pastures on this soil type. Among the perennial clover species, Kenya white clover (7'. semipilosum) showed outstanding recovery from drought and was the only species to produce significantly in autumn. However, it failed to grow in winter-early spring. Within red clover, materials of New Zealand x Moroccan origin substantially outproduced the commercial cultivars. Within white clover, material from Israel, Italy and Lebanon, as well as progeny of a selected New Zealand plant, showed more rapid recovery from drought stress and subsequently better winter growth than New Zealand commercial material ('Grasslands Huia'). The wider use of plant material of Mediterranean origin and of plants collected in New Zealand dryland pastures is advocated in development of clover cultivars for New Zealand dryland situations.

scholarly journals Flavonoid Glycosides in Brassica Species Respond to UV-B Depending on Exposure Time and Adaptation Time

Molecules ◽  
2021 ◽  
Vol 26 (2) ◽  
pp. 494
Author(s):  
Susanne Neugart ◽  
Christiane Bumke-Vogt
Keyword(s):  
Brassica Species ◽  
Flavonoid Glycoside ◽  
Ultraviolet B ◽  
Flavonoid Glycosides ◽  
Production Cycle ◽  
Short Term ◽  
Greenhouse Production ◽  
Adaptation Time ◽  
Quercetin Glycosides ◽  
Kaempferol Glycosides

Recently, there have been efforts to use ultraviolet-B radiation (UV-B) as a biotechnological tool in greenhouses. Leafy Brassica species are mainly considered for their ability to synthesize glucosinolates and are valued as baby salads. They also have a remarkable concentration of chemically diverse flavonoid glycosides. In this study, the effect of short-term UV-B radiation at the end of the production cycle was investigated without affecting plant growth. The aim was to verify which exposure and adaptation time was suitable and needs to be further investigated to use UV as a biotechnological tool in greenhouse production of Brassica species. It is possible to modify the flavonoid glycoside profile of leafy Brassica species by increasing compounds that appear to have potentially high antioxidant activity. Exemplarily, the present experiment shows that kaempferol glycosides may be preferred over quercetin glycosides in response to UV-B in Brassica rapa ssp. chinensis, for example, whereas other species appear to prefer quercetin glycosides over kaempferol glycosides, such as Brassica oleracea var. sabellica or Brassica carinata. However, the response to short-term UV-B treatment is species-specific and conclusions on exposure and adaptation time cannot be unified but must be drawn separately for each species.

Flavonoids and UV Photoprotection in Arabidopsis Mutants

2001 ◽  
Vol 56 (9-10) ◽  
pp. 745-754 ◽  
Author(s):  
Ken G Ryan ◽  
Ewald E Swinny ◽  
Chris Winefield ◽  
Kenneth R Markham
Keyword(s):  
Crucial Role ◽  
Hydroxycinnamic Acid ◽  
Ultraviolet B ◽  
Uvb Radiation ◽  
Wild Type ◽  
Hydroxycinnamic Acid Derivatives ◽  
Quercetin Glycosides ◽  
Kaempferol Glycosides ◽  
Low Levels ◽  
High Level

AbstractWild-type Arabidopsis L. leaves exposed to low ultraviolet-B (U V B ) conditions contained predominantly kaempferol glycosides, with low levels of quercetin glycosides. The flavonoid level doubled on treatment with UVB and an increase in the ratio of quercetin: kaempferol was observed. These results suggest that flavonols protect Arabidopsis plants from UVB damage, and indicate that the flavonoid 3’-hydroxylase (F3’H) enzyme, which converts dihydrokaempferol to dihydroquercetin, may play a crucial role. The tt7 mutant lacks this gene and, after treatment with sub-ambient UVB, contained kaempferol glycosides exclusively, to a level of total flavonols similar to that in wild-type Arabidopsis. Total flavonols after enhanced UVB treatment were higher in tt7 than in similarly treated wild-type plants, and only kaempferol glycosides were detected. Despite this high level, tt7 plants were less tolerant of UVB radiation than wild-type plants. These observations suggests that kaempferol is a less effective photoprotectant than quercetin. The chalcone isomerase (CHI) mutant (tt5) surprisingly did not accumulate naringenin chalcone, and this suggests that the mutation may not be restricted to the CHI gene alone. The concentration of hydroxycinnamic acid derivatives did not change with UVB treatment in most varieties indicating that their role in UV photoprotection may be subordinate to that of the flavonoids.

scholarly journals Caucasian clover performance in a year of severe drought

1998 ◽  
pp. 119-125
Author(s):  
R.N. Watson ◽  
F.J. Neville ◽  
N.L. Bell
Keyword(s):  
White Clover ◽  
Growth Rates ◽  
Volcanic Ash ◽  
Severe Drought ◽  
Summer Drought ◽  
Volcanic Ash Soil ◽  
Summer Growth

In a year of spring-summer drought on a sandy volcanic ash soil, ryegrass/caucasian clover (RG/ CC) and RG/white clover (RG/WC) pastures had similar rapid increases in pasture growth rates during September. Growth rates peaked around 25 October (65-70 kg DM/ha/day) for RG/CC and around 14 October (50-60 kg DM/ha/day) for RG/ WC. As drought intensified the declines in pasture growth rates were similar, but delayed by up to 3 weeks for RG/CC. Both pastures reached minimum summer growth rates of

scholarly journals GROWING LUCERNE FOR DEHYDRATION

1974 ◽  
pp. 80-88
Author(s):  
J.S. Whitelaw
Keyword(s):  
New Zealand ◽  
Summer Drought ◽  
Commercial Development ◽  
Forage Crop ◽  
Export Production ◽  
Plant Expansion

LUCERNE has long been recognized as a highly nutritious forage crop, traditionally utilized for hay and now widely used for grazing stock on the shallower soils subject to summer drought. A recent commercial development in New Zealand is the use of lucerne to produce a dehydrated product. Export production from the Winslow factory has increased from 3000 tonnes in the first season to 14 000 tonnes in the 1973-4 year, and, with an increasing lucerne contract area and plant expansion, production is planned to increase to 30 000 tonnes.

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