Does leaf gas exchange correlate with petiole xylem structural traits in Ulmus laevis seedlings under well-watered and drought stress conditions?

Several studies have shown that petiole xylem structure could be an important predictor of leaf gas exchange capacity, but the question of how petiole xylem structure relates to leaf gas exchange under different environment conditions remains unresolved. Moreover, knowledge of the amount of leaf gas exchange and structural variation that exists within a single species is also limited. In this study, we investigated the intraspecies coordination of leaf gas exchange and petiole xylem traits in 2-year-old seedlings of Ulmus laevis Pall. under well-watered and drought conditions. It was found that all studied petiole xylem traits of the elm seedlings were positively correlated with each other. This shows that the development of petiole xylem structure is internally well-coordinated. Nevertheless, the lower correlation coefficients between some petiole xylem traits indicate that the coordination is also individually driven. Drought stress reduced all studied leaf gas exchange traits and significantly increased intraspecies variation. In addition, drought stress also shifted the relationships between physiological traits and exhibited more structure-function relationships. This indicates the importance of petiole xylem structure in dictating water loss during drought stress and could partly explain the inconsistencies between leaf structure-function relationships studied under optimal conditions. Although several structure-function traits were related, the wide ranges of correlation coefficients indicate that the internal coordination of these traits substantially differs between individual elm seedlings. These findings are very important in the context of expected climatic change, as some degree of intraspecies variation in structure-function relationships could ensure the survival of some individuals under different environmental conditions.

Repeated pregnancy in a bitch, with a diagnosis of extensive cystic endometrial hyperplasia, after the exact determination of the optimal time for breeding.

A 6-year-old bitch was presented to the clinical examination with the aim of determining the optimal time for intrauterine insemination by frozen-thawed semen. The bitch had already had two litters in the past. Extensive cystic endometrial hyperplasia was diagnosed by an ultrasound examination in the bitch. The timing of the endoscopic transcervical insemination by a combination of ultrasonographic examination of the ovaries and determining the progesterone concentrations contributed to the successful conception in the bitch. The ultrasonographic examination of the ovaries represents a non-invasive method which allowed us to view the changes on the ovaries in real time and, thus, is a very suitable method for the specification of the ovulation time in bitches. Cystic endometrial hyperplasia is considered to be a possible cause of infertility. Nevertheless, the bitch repeatedly conceived and had larger litter sizes. Moreover, a considerable reduction in the number of endometrial cysts was observed after the third pregnancy of the bitch. In the described clinical case, the influence of the cystic endometrial hyperplasia on the conception was not demonstrated.

Changes in the mast cell distribution in the canine ovary and uterus throughout the oestrous cycle.

This is the first study describing the relation between the phase of the oestrous cycle and the number of mast cells (MCs) in the canine ovaries and uterine horns. The total number of MCs was counted in cortex ovarii, medulla ovarii, endometrium and myometrium. The number of MCs was compared in all of these areas among the bitches in the early follicular phase, luteal phase and anoestrus. MCs were the most numerous in the early follicular phase and in the luteal phase; however, they were significantly less numerous during anoestrus. Based on the results, it was concluded that the number of MCs in ovaries and uterine horns fluctuates during the oestrous cycle. The results of this study may contribute to clarifying the role of MCs in the reproductive organs of bitches.

A comparison of quality parameters of fresh feline ejaculates collected by three different collection techniques.

The aim of our study was to compare the quality parameters of fresh feline ejaculates collected by three different techniques-urethral catheterization after medetomidine administration (CT), electroejaculation (EE) and epididymal slicing after orchiectomy (EP). A total of 34 adult male cats (Felis catus) were included in the study. In all male cats, the sperm collection was performed under general anaesthesia by three collection methods in the following order: urethral catheterization, electroejaculation and epididymal slicing. The sperm parameters evaluated were as follows: volume, motility, viability, sperm concentration, total sperm count and morphological examination. The highest quality semen parameters were achieved using EE. The comparison of results of the evaluated sperm quality parameters from EE and EP showed significant differences only in one case-the percentage of head abnormalities and lower percentage of head abnormalities were achieved using EE compared to EP: 8.5% (3.0%-21.0%) versus 10.0% (4.0%-22.0%). Semen collected by CT rendered the lowest quality samples when compared to sperm samples collected by EE and EP, especially with respect to the motility and total sperm count which were significantly lower (p < 0.001). Our study showed that sperm samples collected by EE and EP result in better quality of feline ejaculates compared to collection by CT from sperm samples collected from the same male cats. These results demonstrate the necessity of further research of urethral catheterization as a novel technique of semen collection in male cats.