The Iron and Manganese Content of Plants present in the Natural Vegetation of the English Lake District

Estimations of iron and manganese have been made on ninety-sixspecies of plants (including fungi, mosses, ferns, and floweringplants) from a wide range of natural habitats. These plantsnormally contain more of both elements than is usual in cropplants grown on cultivated fields, probably owing to the greateracidity and humus content of the natural soils. The amount presentvaries with the individual species, the plant group, and thetype of habitat. While some species and groups tend to takeup iron or manganese selectively, both the absolute amountsand the ratio of the two elements may vary widely without apparentinjury to the plant. In general, these elements accumulate mostin aquatic plants growing on organic and anaerobic muds. Thelowest amounts are found in species characteristic of flushedbrown earths and in plants from drained acid peats. The fruitingbodies of fungi contain little of either element.     

Some Quantitative Changes in the Fat Metabolism of Germinating Lettuce Seeds and their Inhibition by Coumarin

The fat reserve of lettuce seeds of two varieties, ‘GrandRapids’ and ‘Progress’, was examined. It wasfound to be an unsaturated lipid, closely resembling sunflower-seedoil. The changes in the fat content with time and under treatmentwith thiourea and with coumarin were studied, as were the changesin the acidity of the fat. No free volatile saturated acidswere detected. On hydrolysis the seeds yield one such acid whoseidentity was not finally established and whose origin is uncertain,it not being certain that it is connected directly with fatmetabolism.     

Ion Absorption and Allocation of Carbon Resources in Excised Pea Roots Grown in Liquid Medium in Absence or Presence of NaCl

Freshly excised pea roots (Pisum sativum cv. Alaska) when transferredto growth medium (130 mOsm) or growth medium containing salt( 370 mOsm) suffer an initial osmotic shock and lose water.Contol roots tended to accumulate potassium, particularly inthe apical zone, while those exposed to NaCl accumulated mainlysodium, potassium accumulation being depressed. Exposure tosalinity for 6 d caused increases in root protein, cellulose,uronic acid and lignin content per cell. In roots supplied with¹⁴C-glucose for 24 h immediately after excision there was littledifference in uptake of glucose and in its use in respirationbetween control and salt treated roots. However, there werenoticeable differences in incorporation of labelled carbon intoseveral cell fractions, and particularly into the cellulosefraction in the upper parts of the root. When roots were grownfor six days in culture before being supplied with [¹⁴C]glucose,uptake per root was greater in the 120 mM NaCl treatment, andthe fraction diverted to respiration was decreased by salinity.On a per cell basis incorporation into soluble starch, uronicacid and cellulose fractions was increased in the salt treatedroots. The data obtained are in accord with the previous findingsand are suggestive of increased synthesis of cell wall materials.No conclusion could be drawn as to whether the changes describedare of adaptive value. Pisum sativum L. cv. Alaska, root culture, salinity, osmoregulation, cell wall     

Paired sequence difference in ribosomal RNAs: evolutionary and phylogenetic implications

Ribosomal RNAs have secondary structures that are maintained by internal Watson-Crick pairing. Through analysis of chordate, arthropod, and plant 5S ribosomal RNA sequences, we show that Darwinian selection operates on these nucleotide sequences to maintain functionally important secondary structure. Insect phylogenies based on nucleotide positions involved in pairing and the production of secondary structure are incongruent with those constructed on the basis of positions that are not. Furthermore, phylogeny reconstruction using these nonpairing bases is concordant with other, morphological data.      

CONSUMER'S COLOR ACCEPTANCE OF STRAWBERRY NECTARS FROM PUREE

In two surveys (600 consumers) (1) the importance of color on a consumer's decision to buy strawberry nectar and jam, (2) the consumer's color acceptance of strawberry nectars from puree and adequate products containing colorants from the market as well as specially prepared samples and (3) the associated attributes to these samples were studied. In addition, a test was carried out in order to (4) characterize strawberry color and its changes during storage sufficiently with one value.
Color has a big impact on a consumer's decision to buy strawberry nectars as well as strawberry jam. Neither gender nor age or consumption habits of consumers had a significant impact on color acceptance. For color assessment, an "acceptance factor" (AF) was calculated from colorimetric data that provides processors the prediction of color quality of nectars from puree. Nectars with an AF lower than 0.4 were not accepted, whereas nectars with an AF higher than about 0.7 were described as excellent.

PRACTICAL APPLICATIONS

The results of this study show the first time that it is possible to characterize the color of strawberry products by means of the calculation of an "acceptance factor" (AF =  a */h), and to predict whether the color will be accepted from the consumers or not (excellent [AF > 0.7], acceptable [AF > 0.4] or not acceptable [AF < 0.4]). This data could be used as basis for the production of new strawberry nectars (containing colorants) and the assessment for the stability and shelf life of strawberry products from puree.