Estimating evaporation: A comparison between Penman, Idso-Jackson, and zero-flux methods

A field evaporation—drainage study was conducted to compare three methods of predicting evaporative losses from a bare soil. Two of the methods (modified Penman combination and Idso—Jackson) are dependent only on measurements of atmospheric parameters whereas the third method (plane of zero flux) is dependent only on measurements of soil parameters.A Captina soil profile was wet up and allowed to dry by evaporation and drainage. For the initial two days after infiltration ceased all three methods predicted similar evaporative losses. Differences between the three methods occurred when the soil moisture content at the soil surface controlled the evaporation rates. Under the three drying conditions the three methods behaved somewhat differently in the prediction of the amounts of water evaporated from the soil surface. Lower losses by evaporation were predicted by the Idso—Jackson and zero-flux methods. In the case of the Idso—Jackson method this result was attributed to the influence of clouds on albedo, the impact of wind and the importance of albedo in the predictive equation. For the zero-flux method the decrease in evaporation was due to lower soil water contents and matrix potentials near the surface which resulted in lower transport rates of water to the surface.     

Empirical estimation of thermoreaction curves for the rate of development

If the period is considered during which a certain development of a plant takes place, experience has shown that in many cases there is a strong correlation between temperature and rate of development. A method has been worked out to estimate from phaenologic data a linear or curvilinear relation between the temperature and the rate of development.     

Ploidy races in Actinidia chinensis

Summary Ploidy levels were examined in 26 accessions of Actinidia chinensis: 20 accessions were diploid (2n=2x=58) and 6 accessions were tetraploid (2n=4x=116). There was no evidence of variation in ploidy level within an accession. Our results are consistent with tetraploid A. chinensis coming from a restricted part of China.Interploid crosses within A. chinensis produced only low numbers of seedlings which were mainly triploid. Crossing hexaploid A. deliciosa with pollen of tetraploid A. chinensis produced a large family of plants and those checked were pentaploid.Counts on 83 genotypes of different ploidy levels (2x, 3x, 4x, and 5x) confirmed that the basic chromosome number in Actinidia is 29.     

Atlantic salmon (Salmo salar) prolactin cDNA sequence and its mRNA expression after transfer of fish between salinities

The Atlantic salmon (Salmo salar) has a life cycle that involves inhabiting both fresh and salt water. The control and maintenance of ionic balance is under control of the endocrine system. Prolactin is reportedly an important hormone for the ionic balance of salts in the body fluids of fish, especially during the periods of time spent in fresh water. An Atlantic salmon pituitary cDNA library was constructed in gt 11, from which a full length Atlantic salmon prolactin cDNA was isolated using a chinook salmon (Oncorhynchus tshawytscha) prolactin cDNA probe. The sequence of this clone (ATPRL-5) was determined. Comparison of this sequence and other published sequences showed all the prolactin genes isolated to date are highly conserved. The expression of the prolactin mRNA from adult and juvenile salmon was studied after transfer between salinities. Expression varied in the predicted manner. Adult salmon transferred to fresh water showed large increases in the prolactin mRNA level compared to control fish (>600% increase after 72 h). Only a small difference was observed when smolts (juvenile salmon) were transferred to salt water.     

Inheritance of taste characters and fruit size and number in a diploid Actinidia chinensis (kiwifruit) population

We investigated the variability and inheritance of taste components and fruit size and number in a seedling population of diploid Actinidia chinensisPlanch. We found significant variation in all characters measured. Narrow-sense heritability estimates were high for vitamin C content, titratable acidity (TA), soluble solids content (SSC), fruit weight and dry matter content (DM), but low for glucose content, quinic acid content, and fruit number per vine. The genetic correlations between sugars (except myo-inositol), acids (except quinic acid), TA, vitamin C content, SSC and DM tended to be positive and moderate to high. However, correlations between these characters and fruit weight tended to be negative and moderate to high. The standardised coefficients () of multiple regression showed that SSC was highly dependent on the levels of fructose content, sucrose content and TA. Estimates of relative selection efficiencies (E) suggested that selection using SSC could be an efficient and convenient alternative to direct selection for improvement of sugar levels in kiwifruit. However, selection strategies based on SSC need to take account of its moderate negative correlation with fruit weight. Male and female parents useful for improving acid and sugar composition and fruit size were identified. One family was outstanding, as it combined large fruit size with high levels of SSC and DM.