Seed-borne fungi of Ornithopus sativus during a twenty year storage

Subject to analysis were seed-borne fungi of serradella during a long term storage. The agents causing a significant reduction of seed-borne fungi were: the storage conditions and time (very low seed moisture, approx. 5.5%. no oxygen).

Symbiotic properties of Bradyrhizobium sp. (Lupinus) assayed on serradella plants

Physiological and symbiotic properties of <i>Bradyrhizobium</i> sp. (<i>Lupinus</i>) nodule isolates were compared to the standard slow-growing <i>Bradyrhizobium</i> sp. (<i>Lupinus</i>) strain USDA 3045. Lupine nodules isolates showed typical characteristics for bradyrhizobial strains and nodulated small seed legume, serradella (<i>Ornithopus sativus</i>), in tube test. We observed a permanent physiological segregation of the effective (Fix') and ineffective (Fix-) symbiotic phenotype for all tested bradyrhizobial strains during the growth of serradella in plant tube test. The ultrastructural differences between Fix* and Fix serradella nodules were observed. Rapid and visible nodulation as well as easy assay of the reduction of acetylene make serradella a convenient system for studies of <i>Bradyrhizobium</i> sp. (<i>Lupinus</i>) strains in laboratory conditions.

Comparing the potassium requirements of five pasture species

Potassium (K) deficiency is now common in sandy soils of south-western Australia and the K requirements of most pasture species grown in rotation with crops in the region are not known. In a glasshouse experiment using a K deficient yellow sand, we compared the K requirements of 5 pasture species now commonly grown in the region: French serradella (Ornithopus sativus Brot.) cv. Cadiz, yellow serradella (Ornithopus compressus Brot.) cv. Santorini, balansa clover [Trifolium balansae, classified as T. michelianum Savi var. balansae (Boiss)] cv. Paradana, 2 subterranean clover (Trifolium subterraneum L.) cultivars, cv. Seaton Park (subspecies subterraneum) and cv. Trikkala (subspecies yanninicum), and annual ryegrass (Lolium rigidum Gaud) cv. Wimmera. After 56 days of growth, above-ground growth was harvested and analysed for total K. Mitscherlich curves were fitted to yield of dried shoots, K concentration and K content (K concentration multiplied by yield) of the shoots. These fitted curves were used to determine the amount of K required to produce 75% of the maximum yield of dried shoots, K required to attain a K concentration in dried shoots of 25 g/kg, and K required to achieve a K content in dried shoots of 250 mg K/pot. Annual ryegrass and yellow serradella more effectively used indigenous soil K and applied K to produce dried shoots than the other species and cultivars, with the other species and cultivars requiring about 55% more applied K to produce 75% of the maximum shoot yield. The K content in dried shoots estimated the total K taken up from the soil, and annual ryegrass took up least K from soil, but it required least applied K to produce 75% of the maximum shoot yield, indicating it used the K it took up very effectively to produce shoots. Yellow serradella took up most K and, after annual ryegrass, it needed least applied K to produce the target yield of dried shoots. After yellow serradella, subterranean clover cv. Trikkala took up most K from soil, but it required nearly the most applied K to produce the target shoot yield so it was inefficient at using K taken up to produce the shoots. For all the other species and cultivars, K requirement was similar as assessed by yield or K content data. The critical concentration of K required for 90% maximum yield of dried shoots was about (g K/kg) 24 for balansa clover, 23 for both subterranean clover cultivars, 21 for yellow and French serradella, and 15 for annual ryegrass.

The role of fractures and lipids in the seed coat in the loss of hardseededness of six Mediterranean legume species

Changes in the seed coat morphology of 12 annual legumes were studied using environmental scanning electron microscopy (ESEM). The seeds of Biserrula pelecinus L. cv. Casbah, Ornithopus sativus cv. Cadiz, Trifolium clypeatum L., T. spumosum L., T. subterraneum L. cv. Bacchus Marsh, Trigonella balansae Boiss. & Reuter., Trigonella monspeliaca L. and Vicia sativa subsp. amphicarpa Dorthes (morthes.) were examined by ESEM after exposure to field conditions for 6 months, while those of Medicago polymorpha L. cv. Circle Valley, Trifolium clypeatum L., T. glanduliferum Boiss., T. lappaceum L., T. spumosum L., and T. subterraneum L. cv. Dalkeith, were examined after 2 years' exposure. The entry of water into seeds was followed by covering various parts of the seed coat with petroleum jelly and soaking the treated seeds in dyes.As the seeds softened over time, more and larger fractures appeared on the seed coat. Water entered the seed either through fractures, over the seed coat as a whole or through the lens. It is hypothesized that the formation of fractures occurs after physicochemical changes in the seed coat, probably associated with changes in the amount and nature of seed coat lipids.The newly matured whole seeds of M. polymorpha cv. Circle Valley, T. clypeatum, T. glanduliferum, T. lappaceum, T. spumosum, and T. subterraneum cv. Dalkeith were analysed for lipid content in 1997. The seed coats of T. subterraneum cv. Dalkeith and T. spumosum were separated from the cotyledons and examined in detail for lipid content.The lipid content of whole seeds ranged from 48 (T. lappaceum) to 167 mg/g (T. subterraneum cv. Dalkeith). Total lipid of the whole seeds of T. subterraneum cv. Dalkeith and T. glanduliferum declined by about 9 mg/g over 2 years, while in T. spumosum it declined by about 17 mg/g.In contrast, the major fatty acids in the seed coat declined by 0·67 mg/g over the 2 years. Change in seed coat lipids showed a marked similarity to changes in hardseededness for both T. subterraneum cv. Dalkeith and T. spumosum. The results strongly suggest that seed softening is associated with loss of lipids in the seed coat, because lipids have physical characteristics that are altered at temperatures experienced in the field.

Productivity and persistence of Trifolium hirtum, T. michelianum, T. glanduliferum and Ornithopus sativus sown as monocultures or in mixtures with T. subterraneum in the south-eastern Australian wheat belt

The persistence and productivity of 5 annual pasture legume species: French serradella (Ornithopus sativus Brot) cv. Cadiz; rose clover (Trifolium hirtum All.) cv. Hykon; balansa clover (T. michelianum Savi) cv.�Frontier; gland clover (T. glanduliferum) cv. Prima) and subterranean clover (T. subterraneum L.), grown in monocultures or as binary mixtures with subterranean clover cv. Nungarin, were examined on an acid soil (pH�4.7) in the low rainfall wheat belt of south-eastern Australia over a 3-year period of continuous pasture.

Comportamento de adubos verdes de inverno na região serrana fluminense

O objetivo deste trabalho foi o de avaliar o comportamento de espécies de adubos verdes de inverno, em um Cambissolo Háplico Tb distrófico, sob duas condições de fertilidade, a 1.100 m de altitude. Dois experimentos de campo foram conduzidos em Nova Friburgo, RJ, utilizando as seguintes espécies: aveia-preta (Avena strigosa Schieb.), azevém-anual (Lollium multiflorum Lam.), chícharo (Lathyrus sativus L.), ervilhaca-comum (Vicia sativa L.), ervilhaca-peluda (Vicia villosa Roth), utilizada somente no segundo experimento, serradela-flor-rosa (Ornithopus sativus Brot.), tremoço-amarelo (Lupinus luteus L.), tremoço-branco cultivar Comum (Lupinus albus L.), tremoço-branco cultivar Multo Lupa Doce (Lupinus albus L.), tremoço-branco cultivar TRM 881 (Lupinus albus L.), trevo-branco (Trifolium repens L.), trevo-vermelho cultivar Achylesmarium (Trifolium pratense L.), e trevo-vesiculoso cultivar Jacuí 52 (Trifolium vesiculosum Savi). O delineamento experimental foi em blocos ao acaso, com três repetições. As espécies que mais se destacaram na produção de massa seca e acumulação de N na parte aérea, sob condições de boa fertilidade no solo, foram as três cultivares de tremoço-branco, o tremoço-amarelo, a ervilhaca-comum e a aveia-preta. Sob condições de baixo teor de P, Ca e Mg no solo, as que mais se destacaram foram as três cultivares de tremoço-branco e a aveia-preta.

Alfalfa mosaic and pea seed-borne mosaic viruses in cool season crop, annual pasture, and forage legumes: susceptibility, sensitivity, and seed transmission

Field experiments determined the susceptibilities and sensitivities of a wide range of crop, annual pasture, and forage legumes to infection with alfalfa mosaic (AMV) and pea seed-borne mosaic (PSbMV) viruses. Seed harvested from most of the species was tested for virus seed transmission. With AMV, all 23 Cicer arietinum genotypes tested were ranked as highly susceptible, and 9 out of 19 Lens culinaris genotypes as highly susceptible, 8 susceptible, 1 moderately resistant, and 1 resistant. Genotypes of Vicia narbonensis (5), Lathyrus cicera (5), L. sativus (5), L. ochrus(2), V. sativa (1), and V. benghalensis (1) were highly susceptible, susceptible, or moderately resistant. Genotypes of Pisum sativum (5) and V. faba(3) were susceptible, moderately resistant, or resistant but 1 genotype of V. faba was not found infected. Sensitivities ranged from low in L. ochrus to high in some genotypes of most species tested exceptV. benghalensis. The 20 genotypes (19 species) of pasture and forage legumes ranged from ‘not found infected’ in Hedysarum coronarium to ‘highly susceptible’ in Ornithopus sativus and Trifolium resupinatum. Sensitivity varied from low in T. michelianum to very high in Biserrula pelecinusand Ornithopus sativus. With PSbMV, the genotypes ofP. s a t i v u m (17), V. narbonensis (5), and L. cicera(3) were ranked as highly susceptible, susceptible, or moderately resistant, while those of L. ochrus(3), V. faba(6), V. sativa (3), V. benghalensis (2) and V. ervilia(1) were either moderately resistant or resistant. The genotypes of C. arietinum (6) and Lens culinaris (6) were all resistant. With L. sativus, 2 genotypes were resistant and 1 was not found infected. Sensitivities ranged from low in some P. sativum genotypes to high in some ofL. ciceraand V. narbonensis. The seed coats of 9 crop legume species developed necrotic ring markings, a serious quality defect due to PSbMV infection. Of the 19 genotypes (1/species) of pasture and forage legumes, 4 were resistant with only symptomless infection developing and the remainder not found infected. In glasshouse inoculations to genotypes not found infected in the field, AMV infected V. faba cv. Ascot systemically butH. coronarium cv. Grimaldi (with AMV) and L. sativus BIO L254 (with PSbMV) only became infected in inoculated leaves, H. coronarium developing a localised hypersensitive reaction. Seed transmission of AMV was detected in L. cicera(2%), L. sativus (0.9–4%), V. benghalensis(0.9%), V. narbonensis (0.1%), and V. sativa (0.7%). It was also found in 15 pasture and forage legume species, ranging from 0.05% in T. michelianum to 7% in Trigonella balansae. Seed transmission of PSbMV was detected in L. cicera(0.4%), L. clymenum (5%), L. ochrus (0.7%), L. sativus (1%), P sativum(1–18%), V. benghalensis (0.1%), V. faba (2%), and V. sativa (0.3%). The implications of these findings and their importance to the management of these and other virus diseases are discussed.