Fruit growth of cucumber in relation to assimilate supply and sink activity

Schapendonk, A.H.C.M. and Brouwer, P., 1984. Fruit growth of cucumber in relation to assimilate supply and sink activity. Scientia Hortic., 23: 21--33. Assimilate distribution in Cucumis ativa, cultivar 'Farbio', was studied during 36 days after emergence of the inflorescense in the 5th axil. The interaction between vegetative growth and reproductive development was exam-ined. Daily net photosynthesis and the related assimilate supply were calculated by a simulation model. The actual dry matter accretion of vegetative and reproductive organs was derived from non-destructive measurements of organ dimensions and subsequent convertion to dry matter by statistical relations. Integrated over the total period of in-vestigation, dry matter accretion derived either from the calculated assimilate supply or from ac~;ual measurements agreed well. However, a significant discrepancy appeared in the dynamic resolution where apparent periods of assimilate surplus were followed by periods of apparent shortage of assimilates. In this respect, the regulation of temporary storage and subsequent remobilization of assimilates i studied in relation to source--sink interactions. A hypothesis is formulated that relates the dynamics of fruit growth to assimilate supply and the sink activity of individual fruits. Keywor,~s: competition for assimilates; cucumber; fruit growth; photosynthesis