Characteristics of canopy interception and its simulation with a revised Gash model for a larch plantation in the Liupan Mountains,China

Canopy interception is a significant proportion of incident rainfall and evapotranspiration of forest ecosystems. Hence, identifying its magnitude is vital for studies of eco-hydrological processes and hydrological impact evaluation. In this study, throughfall, stemflow and interception were measured in a pure Larix principis-rupprechtii Mayr.(larch) plantation in the Liupan Mountains of northwestern China during the growing season(May–October) of 2015, and simulated using a revised Gash model. During the study period, the total precipitation was499.0 mm; corresponding total throughfall, stemflow and canopy interception were 410.3, 2.0 and 86.7 mm,accounting for 82.2, 0.4 and 17.4% of the total precipitation, respectively. With increasing rainfall, the canopy interception ratio of individual rainfall events decreased initially and then tended to stabilize. Within the study period, the simulated total canopy interception, throughfall and stemflow were 2.2 mm lower, 2.5 mm higher and0.3 mm lower than their measured values, with a relative error of 2.5, 0.6 and 15.0%, respectively. As quantified by the model, canopy interception loss(79%) mainly consisted of interception caused by canopy adsorption, while the proportions of additional interception and trunk interception were small. The revised Gash model was highly sensitive to the parameter of canopy storage capacity,followed by the parameters of canopy density and mean rainfall intensity, but less sensitive to the parameters of mean evaporation rate, trunk storage capacity, and stemflow ratio. The revised Gash model satisfactorily simulated the total canopy interception of the larch plantation within the growing season but was less accurate for some individual rainfall events, indicating that some flaws exist in the model structure. Further measures to improve the model's ability in simulating the interception of individual rainfall events were suggested.     

Viability of cattle sperm under different storage conditions in Cameroon

A study was carried out to evaluate the viability of extended cattle semen, without freezing, under different storage conditions. The semen was collected from Holstein Friesian bulls using artificial vaginas. The semen was extended and stored in a 3-by-4 factorial design (storage system × ice change). The storage media were ice boxes, buckets, and refrigerator. The ice in these media was either replaced daily, on the first and third day, first day only, or no ice at all after the semen collection. Results showed an overwhelming evidence of the effect of storage medium and ice change on sperm viability (P < 0.0001). Individual motility before processing was highest in the refrigerator with averages of 44.5%, 39.5% in ice boxes, and 10% in buckets during the 8-day experiment. There was no significant difference (P > 0.05) in progressive motility after processing in the refrigerator (34%) and in ice boxes (33%) but significantly higher (P < 0.01) to the 10% obtained in buckets. It was shown that spermatozoa in the ice box retained 45% individual motility up to the sixth day after semen was collected on the condition that the ice was changed on the third day. Progressive motility after processing in the ice box was 40% up to the sixth day with the ice changed on the third day while the spermatozoa were well preserved up to the fourth day in the same medium if the ice put on the first day was not changed. This study shows that, if farmers plan to inseminate cows within the first day after semen collection, they can use buckets with ice for the transportation of the extended semen ampoules from the artificial insemination center. Otherwise, the semen needs to be kept in ice boxes and the ice changed on the third day after collection and this semen could be used within a week.     

Cloning and tissue expression of the equine transferrin receptor

Background: Characterization of anemia in horses presents a challenge, as they do not release reticulocytes into peripheral blood. Transferrin receptor (TfR) expression is highest on erythroid cells in people and rats, and measurement of a soluble serum form (sTfR) is used to quantify erythropoiesis in these species. We hypothesized that equine TfR (eTfR) expression is similar in quantity and distribution to that in these other species and thus has potential for characterization of the regenerative response in anemic horses. Objective: This study was conducted to clone and sequence the eTfR gene and measure expression levels using quantitative real‐time PCR and immunohistochemical (IHC) staining. Methods: Total RNA from equine bone marrow was used to produce cDNA. The eTfR gene was amplified using pooled gene‐specific primers, and PCR products were sequenced. Rapid amplification of cDNA ends was used to obtain the first 22 nucleotides of the coding sequence. Quantitative PCR was performed using eTfR gene‐specific primers, and IHC staining was used to localize TfR protein expression. Results: The deduced amino acid (aa) sequence (767 aa) of the eTfR was 75–83% identical with sequences of the receptor in several other mammals. As in people and rats, eTfR mRNA expression was highest in the bone marrow, and distribution in other tissues was also similar. Conclusion: The eTfR gene is similar to that of other mammals in structure and expression levels. We hypothesize that it is also similar in function and that, following development of an immunoassay, determining sTfR concentrations will be useful for identifying the regenerative response in anemic horses.     

Canopy photosynthesis,stomatal conductance and yield ofSolanum tuberosum grown in a warm climate

Selected potato (Solanum tuberosum L.) genotypes were grown in the field from May to September during 1984 and 1985, to study their growth and gas exchange responses in a warm climate. The parameters measured were leaf area index (LAI), canopy photosynthesis on ground area basis (CPn-Ga), stomatal conductance, dry matter partitioning and yield. The LAI ranged from 1.40 for Dakchip to 6.60 for Pungo during August 1984. The LAI also differed significantly among the potato genotypes for the three samplings during 1985. Atlantic, Chipbelle and DTO-33 showed no decline in their LAI up to 73 days after planting (DAP), indicating a better heat-stress tolerance response than the other genotypes. During both years, CPn-Ga differed significantly among the genotypes and Pungo had higher CPn-Ga than all the other genotypes. Mean CPn-Ga rates were 1.72 and 4.34 g CO₂ m^?2hr^?1 during 1984 and 1985, respectively. Mean adaxial and abaxial stomatal conductances were 0.86 and 1.46 cm sec^?1, during 1984, and stomatal conductances were similar for both years. Stomatal conductance did not appear to limit gas exchange in potato leaves. Dry matter partitioning to tubers ranged from 8.9% for Pungo to 55.5% for Atlantic 67 DAP during 1984. At final harvest, July 19, 1985, dry matter partitioning to tubers varied from 47.5% for Pungo to 69.9% for Chipbelle. The tuber yield ranged from 9.6 to 27.8 MT/ha. This study indicated that Atlantic and La Chipper have potential for growing in a warm climate.     

Reliability of pelvimetry is affected by observer experience but not by breed and sex: A cross-sectional study in beef cattle

Pelvis size plays an important role to prevent dystocia in cattle caused by the foeto-maternal disproportion in commonly primiparous females. The reproducibility and repeatability are two important aspects for the reliability of the measurements to use in the selection of cattle for culling. Pelvic measures were taken with a Rice pelvimeter from 224 young cattle (180 females and 44 males) of four beef breeds in South Africa. One experienced and two inexperienced observers each measured pelvic height and width twice. The proportion measurements with a maximum difference of 0.5 cm within animal compared with the first measurement by the experienced observer are around 80% and by the inexperienced observers around 50% for pelvic height and around 60% for pelvic width. Breed and sex do not affect the reliability of pelvimetry by an experienced observer. Under- and overestimation of pelvis size were observed in inexperienced observers, which seems to be unrelated to breed and sex.