A Low-Cost, Easy-to-Install Flow Culture System Suitable For Use in a Constant Environment Cabinet

The Construction of a low-cost, easy-to-install flowing culturesystem with a total capacity of 360 1 of solution, a flow rateapproaching 11 per pot per minute, and equipped for warmingis described. The system can be easily modified. As described here it is builtinto a controlled environment cabinet where a precise controlof the aerial environment is combined with the maintenance ofnutrient concentrations in the solution within acceptable limits.     

Estimates of Stability Parameters in Dioscorea deltoidea Wall

Estimates of stability parameters for various traits in Dioscoreadeltoidea revealed that some characters, such as, per cent diosgenincontent in tubers, stem thickness and leaf breadth were fairlystable traits. Other characters, i.e. tuber length, tuber branchingand petiole length were not stable and were greatly influencedby the environment. The stability of fifteen genotypes variesfrom character to character and six genotypes were found tobe most stable for the majority of the characters. The significantgenotypic regression on the environment indicated that it shouldnot be difficult to breed D. deltoidea strains which shouldperform fairly well under diverse environmental conditions andto recognize the most desirable properties of a genotype tobe released as a variety for wide cultivation. Diosgenin, stable traits, heritable characters, environmental effect, adaptive genotypes     

Determination of the Relationship between Nutrient Uptake Rate and Solution Concentration at the Root Surface under Field Conditions: 32P-Orthophosphate Uptake by Apple Roots

The relationships between the rates of uptake of ³²P-labelledorthophosphate per unit length, surface area and volume of rootand the concentration of ³²P-orthophosphate in solution at theroot surface were determined in a solution depletion experimentconducted in a root laboratory, using a part of the currentseason's roots of a 3.5-year-old composite apple tree growingunder field conditions. The results are compared with thoseof a previous experiment on young M.9 rootstocks grown in controlledenvironment. The rate of P uptake per unit root of the field-grown tree increasedapproximately linearly with P concentration in the externalsolution over the range 0.8–10.0 mmol m^–3, confirmingthe results of the growth cabinet experiment However, at anygiven external concentration, uptake rate per unit root of thefield-grown tree was lower than that observed in the growthcabinet experiment. Possible reasons for this difference arediscussed.