The effects of sugars and other carbohydrates, vitamins, hormones, complex additives, temperature, light, pH, atmosphere and its components, and moisture are reviewed. Orchid mycorrhiza, symbiosis and asymbiotic nutrition are also reviewed.

Surfactants, representing 3 non-ionic and 1 amphoteric series of homologs exhibited marked differences in their lethal and non-toxic effects on HeLa cells. Toxicity of non-ionics generally decreased inversely with increasing hydrophilic chain length and increased with increasing size of the lipophile. Lethal levels of the surfactants coincided with surface tension reduction of the media to 45 dynes cm-1 or below. Surface tensions of non-toxic concentrations were substantially higher than those for toxic levels. Non-toxic doses were, therefore, below the critical micelle concentration of the surfactants evaluated. The data suggest that physical properties are a principal cause of the toxic effects of these detergents on HeLa cells.

Summary: Quantitative determinations of a number of naturally occurring D‐hexoses and their oligosaccharides can be accomplished by combinations of enzymatic methods without prior separation of the sugars. These spectrophotometric methods employ readily‐available enzymes and commercial reagents. The procedures are particularly useful for the quantitative analysis of fructofuranosides, such as raffinose or stachyose, in the presence of sucrose, glucose and/or fructose; maltose or lactose mixed with galactose and/or glucose; melibiose in mixtures with raffinose, and other combinations.

Dieffenbachia may well be the most toxic genus in the Araceae. Calcium oxalate crystals, a protein and a nitrogen-free compound have been implicated in the toxicity, but the available evidence is unclear. The plants have also been used as food, medicine, stimulants, and to inflict punishment. © 1982.

Summary: Following exposure of Cattleya leaves to 14CO2 in the dark, labelled malate, citrate and an unidentified compound were detected by thin layer chromatography. This is interpreted to suggest the existence in Cattleya leaves of a dark CO2 fixation pathway which may be similar to that found in other plants which can fix large amounts of carbon in the dark.

Pollination causes increases in FW [fresh wt] and DW [dry wt] of Cymbidium ovaries and gynostemia. It also initates FW losses in perianth segments. Auxin (NAA) [naphthaleneacetic acid] applications to the stigma have the same effects except that FW of ovaries decreases. All segments of unpollinated flowers increased in DW, whereas FW variations were minimal. These weight changes reflect the aging and subsequent death and/or redifferentiation and further development of pollinated and/or unpollinated orchid flowers.

Seeds of C. aurantiaca grown asymbiotically on a medium containing sucrose as the sole source of organic carbon developed into leaf-bearing plants. Those sown on the same medium without sugar reached the protocorm stage but did not differentiate further. Cross transfers of seedlings between the 2 media indicated that following 21-30 days of growth on the sucrose-containing medium, subsequent development may proceed in the absence of sugar. Levels of chlorophyll and ribulose-1,5-diphosphate carboxylase were monitored and related to the ability of young seedlings to photosynthesize. A direct relationship between chlorophyll content and photosynthesis was not found. Increases in the activity of the enzyme were closely paralleled by increases in photosynthesis. A direct relationship was not found between chlorophyll a/b ratios and photosynthetic capacity. Germinating seeds and seedlings grown in the absence of exogenous carbohydrate were unable to convert appreciable amounts of labeled acetate to sugar.

The major portion of IAA-2-14C, applied to stigmas of whole flowers of Angraecum cv. Veitchii and Cattleya cv. Porcia Cannizaro, as well as to excised gynostemia of the latter, was immobilized at the point of application. A limited amount of nonpolar transport occurred. Some of the auxin was conjugated into IAA-aspartate in a process which is inhibited by cycloheximide, suggesting a requirement for de novo protein synthesis. Because the effects of pollination and auxin application spread quickly to floral segments, additional substances, from pollen or produced by pollinated flowers, may participate in the regulation of postpollination phenomena in orchid flowers.