Screening for boron tolerance in wheat (T. aestivum) by solution culture in filter paper

A new screening technique for tolerance to high concentrations of boron, namely a filter paper technique, and a soil experiment were compared to investigate the response of wheat genotypes known to differ in tolerance to high concentrations of boron.Under high boron concentrations in filter papers, the more tolerant genotypes had significantly longer roots than those of the more sensitive genotypes. There was no significant correlation between the root lengths at the control treatment and the other three boron treatments (50, 100, 150 mg B L^-1). Thus, the differences in root lengths at the high boron treatments could not be attributed to inherent differences in root growth but to the genetic variation in response to high boron concentrations among varieties.Root lengths at the three boron treatments in filter papers were highly significantly correlated with the three characters determined for plants grown in soil containing high levels of boron, namely the concentrations of boron in the shoots, plant dry weight and plant symptoms, indicating that root length could be used as a selection criterion in a genetic study or breeding program for boron tolerance.Department of Plant Science, Roseworthy Campus, University of Adelaide     

Clinical pathology of nestling marabou storks in Uganda

Packed cell volumes (PCV) and plasma chemistry parameters were measured in 20 nestling marabou storks (Leptoptilos crumeniferus) in January 2003 that were a part of a colony located in the center of the city of Kampala, Uganda. There were no significant differences (P> or =0.05) in plasma chemistry values or PCV between sexes with the exception of globulin and total plasma protein values, which were higher in females. There were significant differences (P< or =0.05) in blood glucose, creatine kinase, and globulin levels between birds of different body weight. Total plasma protein, uric acid, phosphorous, and creatine kinase were generally higher relative to published data on other avian species, including nestling white storks (Ciconia ciconia).     

Dynamics of nutrient remobilisation from seed of wheat genotypes during imbibition,germination and early seedling growth

The changes in nutrient content of grain tissues and seedling parts of two wheat genotypes (Triticum aestivum L., Excalibur and Janz) with low or high seed Zn content were followed from imbibition to early seedling development (12 days). The grains were separated into seed coat, endosperm and embryo, while the seedlings were separated into roots and shoots. The dry weight of the seed coat did not change throughout the experimental period, whereas the endosperm weight declined rapidly from day 4 onward. The weight of embryo did not show any difference between and within cultivars. About a half of seed Zn was remobilised into shoot and roots during 12 days of growth, regardless of the initial seed Zn content in both genotypes. The seed coat contained 55–77% of the total seed nutrients in the two wheat genotypes, except in the case of S (around 40%). Manganese, Fe, Ca, K, and P were remobilised effectively from the seed coat as well as from the endosperm, while remobilisation of Zn and Cu was relatively less from the seed coat than from the endosperm. After 10 days of growth, all nutrients monitored were completely remobilised from the endosperm. Remobilised K was directed primarily into shoots; an increase in K content in shoots was relatively higher than the accumulation of dry matter, with a consequent increase in K concentration in shoot tissue. The remobilisation of some nutrients (eg. Fe, Ca and Zn) from various grain tissues during inbibition, germination and early growth is different from the remobilisation in more mature plants.     

Clinical pathology and morphometrics of African fish eagles in Uganda

Packed cell volumes (PCVs) and plasma chemistry parameters were measured in 15 adult and 18 nestling African fish eagles (Haliaeetus vocifer) sampled from June 2002 through January 2003 in Uganda. Morphologic measurements were obtained from 15 adult eagles. All eagles were examined for blood parasites and sexed by examination of DNA from red blood cells. Ten adults and eight nestlings were sampled from Lake Mburo and five adults and 10 nestlings were sampled from Lake Victoria near Entebbe, Uganda. Analysis of variance was conducted to assess the association between site, age, sex, and plasma chemistry parameters and the association between sex and morphologic characteristics. Plasma chemistry values for nestling and adult African fish eagles were similar to those reported for other captive and free-ranging eagle species. Packed cell volumes for nestling African fish eagles were markedly lower than values reported for nestlings of other eagle species, although the mean estimated age of nestlings sampled also was lower. A significant association (P < or =0.05) was found between PCV of nestling eagles and study site (lower at Lake Mburo) but no association was found between PCV and nestling body weight (P> or =0.05). An unidentified Plasmodium sp. was present in erythrocytes of three nestlings from Lake Mburo. No other blood parasites were seen. There was significant variation (P< or =0.05) in PCV, calcium, phosphorous, potassium, cholesterol concentrations, and creatine kinase activity between adults and nestlings; all were lower in adults. Aspartate transaminase activity was higher in adults. Like other Haliaeetus sp., body weight, bill depth, culmen length, footpad length, and hallux length as well as bill depth measurements were significantly (P < or = 0.05) greater for females than males. The objective of the study was to provide baseline biologic and physiologic information that may prove useful in the management and study of captive and wild populations of African fish eagles.     

Identification of genetic loci associated with ear-emergence in bread wheat

A doubled haploid population constructed from a cross between the South Australian wheat cultivars ‘Trident’ and ‘Molineux’ was grown under winter field conditions, under field conditions over summer and under artificial light both with and without vernalisation. The duration from planting to ear-emergence was recorded and QTL associated with heading date were detected using a previously constructed genetic linkage map. Associations were shown with chromosomal regions syntenous to previously identified photoperiod (Ppd-B1) and vernalisation (Vrn-A1) sensitive loci. Additional QTL associated with time to heading were also identified on chromosomes 1A, 2A, 2B, 6D, 7A and 7B. Comparisons between the genetic associations observed under the different growing conditions allowed the majority of these loci to be classified as having either photoperiod-sensitive, vernalisation-sensitive or earliness per se actions. The identification of a photoperiod-sensitive QTL on chromosome 1A provides evidence for a wheat gene possibly homoeologous to Ppd-H2 previously identified on chromosome 1H of barley. The occurrence of a putative major gene for photoperiod sensitivity observed on chromosome 7A is presented. The combined additive effects at these loci accounted for more than half the phenotypic variance in the duration from planting to ear-emergence in this population. The possible role of these loci on the adaptation of wheat in Australia is discussed.     

Mercury and persistent organic pollutant concentrations in African fish eagles, marabou storks, and Nile tilapia in Uganda

The purpose of this research was to evaluate persistent organic pollutant (POP) and mercury concentrations in tissues of African fish eagles (Haliaeetus vocifer) and Nile tilapia (Oreochromis niloticus) from Lake Victoria near Entebbe and Lake Mburo, Uganda. Marabou stork (Leptoptilos crumeniferus) nestlings from urban Kampala (40 km from Entebbe) also were sampled for POPs and mercury. Total mercury was measured in the breast feathers of eight nestling and 10 adult African fish eagles from Lake Mburo, 10 nestling and five adult African fish eagles from Lake Victoria near Entebbe, and 20 nestling marabou storks from Kampala from June 2002 through January 2003. Mercury concentrations in all samples were below levels associated with adverse effects in similar species. Mercury concentrations were significantly higher in eagle adults and nestlings from Entebbe than in adults and nestlings from Lake Mburo (P< or =0.05). No significant differences (P> or =0.05) were found in mercury concentrations between sexes or between the entire fish eagle population sampled at Entebbe and marabou stork nestlings sampled at nearby Kampala. Plasma samples from the same birds were analyzed for 1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane, aldrin, hexachlorocyclohexane (alpha-HCH), dieldrin, endrin, heptachlor and their metabolites, as well as total polychlorinated biphenyls (PCBs). Nile tilapia whole-body cross sections collected from Lake Mburo (n=3) and Lake Victoria near Entebbe (n=8) also were analyzed for these POPs and mercury. No samples contained POPs or PCBs at the limits of detection except for 4,4'-1,1-dichloro-2,2-bis(4-chlorophenyl)ethylene in five adult eagle plasma samples (0.0026+/-0.0015 ppm wet weight) and five Nile tilapia samples (0.002+/-0.001 ppm wet weight) from Entebbe.