Phosphorus concentration in barley (Hordeum vulgare L.) seed: Influence on seedling growth and dry matter production

The effect of phosphorus (P) concentration in barley seed on seedling growth has not been much investigated. Consequently, two experiments were conducted in the greenhouse to determine the effect of P concentration in barley seed (Hordeum vulgare L., cv. Empress) on the seedlings grown in sand-filled boxes receiving a culture solution without P. Seeds were selected with three P concentrations: high-P (113.0 mmol P kg⁻¹), medium-P (80.7 mmol P kg⁻¹) and low-P (54.9 mmol P kg⁻¹). At 21 days after sowing, the shoot and root yield or shoot height was the least with seedlings from low-P seed. In the other experiment, high-P and low-P seeds were wetted with distilled water or with a solution of 25.8 cmol L⁻¹ of NaH₂PO₄ for 24 h, and then grown for 31 days. Solution P had been imbibed by seeds whether low or high in native P, but only the imbibed P held by low native P seed benefited seedling dry matter accumulation and shoot elongation. The lack of benefit from seed-imbibed P on seedlings grown from high-P barley seed was associated with low recovery of the imbibed P in those seedlings.     

Variation in soil seed bank species composition of a dry coniferous forest: spatial scale and sampling considerations

In order to assess the effects of disturbance on soil seed bank spatial structure, variation in seed bank species composition was analyzed at two spatial scales in mature (undisturbed) and recently disturbed stands of Interior Douglas-fir forest in south-central British Columbia. Coarse-scale analysis among stands 10–100 km apart using Multi-Response Permutation Procedures showed that individual mature stands were mainly characterized by unique seed bank species compositions. Disturbance had an homogenizing effect on seed bank species composition at the coarse scale––there was less variability among stands following disturbance by both low and high severity fires, and by non-salvage logging. In contrast, finer scale analysis among sampling units c. 10 m apart showed that heterogeneity in seed bank species composition was greater on severely burned and logged sites, commensurate with greater levels of soil disturbance, than on lightly burned and undisturbed sites. Despite the high intensity of seed bank sampling (sixty 25 cm² soil samples from each of 16 sites), species-area curves leveled off only when infrequent species were removed from the dataset. The number of seed bank samples required to account for the common species ranged from 84 on severely burned sites, to 196 on undisturbed sites; more than the 240 samples collected per disturbance class in this study would have been required to account for the remaining infrequent species. Overall, this study highlights the importance of sampling intensively within multiple stands to capture the variation in species composition inherent to these dry coniferous forest soil seed banks.     

Transcervical endometrial biopsy in the baboon: Effects on the menstrual cycle and relations to protein and dry matter content and histology

The baboon has been used increasingly for reproductive studies. While hormonal regulation of the menstrual cycle and ovulation as well as the endocrinology of gestation have been reported, little information is available describing endometrial parameters. It is the purpose of this paper to describe the ease with which repeated transcervical biopsies can be performed, to describe baseline endometrial protein and dry weight data and to demonstrate that the biopsy procedure itself does not significantly affect the baboons' ability to continue normal menstrual cycle function. Endometrial biopsy samples were taken throughout the menstrual cycle under light ketamine anesthesia. Protein and dry weight contents were determined. Endometrial biopsies Protein and dry weight contents were determined. Endometrial biopsies averaged 25 mg (wet weight) and contained 7.54% protein and 16.3% dry matter. The formulas (Y = a + bx) which expressed the linear relationships between wet weight (mg), protein (μg) and dry matter (μg) content and the correlation coefficients (r) were as follows: between wet weight and protein content – wet weight = 5.58 + 10.0 (protein), Sxy = 4.83, r = 0.883; between wet weight and dry weight – wet weight = 1.99 + 7.94 (dry weight), Sxy = 4.52, r = 0.904; between protein and dry weight – protein = 0.446 + 0.446 (dry weight), Sxy = 4.82, r = 0.870. All three linear regression coefficients were statistically significant (P < 0.001). No significant cyclical patterns in either protein or dry matter content were demonstrable throughout the menstrual cycles. The average length of all nonbiopsy cycles was 32.4 ± 2.7 days and 32.8 ± 3.6 days for those in which biopsies were taken. Similarly, follicular and luteal phase lengths for nonbiopsy and biopsy cycles were 15.4 ± 2.3 and 15.5 ± 2.8 days and 16.9 ± 2.2 and 17.2 ± 3.2 days, respectively. The time required for sex-skin swelling to decrease from maximum to minimum during the luteal phase was shorter, but the quiescent stage was equally lengthened. It was concluded that the endometrium of the baboon was easily accessible for study without causing serious alterations in menstrual cycle function. These studies further demonstrate the potential of the baboon as a model o reproductive studies. In fact, the baboon may well the only practical primate model available for endometrial studies.     

The disappearance of an hsc70 species in mung bean seed during germination: purification and characterization of the protein

We have purified a 73 kDa protein from the cytosolic fraction of mung bean seeds. It comprises 0.5–1% of the total protein in seeds. This purified protein is a bona fide hsc70 on the basis of several lines of evidence. First, antibodies against bovine brain hsc70 cross-react with the purified 73 kDa protein. Second, the purified protein comigrates on two-dimensional gels with one of the heat-inducible hsc70s in mung bean seedlings. Third, similar to other hsc70 species, the purified 73 kDa protein has a high affinity for ATP. Finally, the hydrolysis of ATP by the purified protein can be stimulated by peptides; ATPase activity increases from 40 nmol/h to 165 nmol/h per mg of protein. The purified mung bean hsc70 autophosphorylates at a substoichiometric level. Moreover, the amount of this hsc70 species diminishes while new species of hsc70s appear after germination, suggesting that the expressionof hsc70 in mung bean is subject to developmental regulation.