Submitted to: Seed Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/10/1996
Publication Date: N/A
Interpretive Summary: Germination and early plant development are controlled by physiological mechanisms. These, in turn, are controlled by environmental conditions. Cucumber (Cucumis sativus) seed germination and stand establishment are reduced in cool soils. Seed of the cvs. 'Arkansas Little Leaf' and 'Earlipik 14' were incubated for up to 168 hrs at 13.9, 15.6 and 20 deg C. Seed were sampled periodically and tested for content of minerals and presence of proteins. For 'Earlipik 14', but not 'Arkansas Little Leaf', there was leakage of minerals over time. Protein profiles at 20 deg C were different than at 13.8 and 15.6 deg C. The data suggests that low cucumber germination rates at suboptimal temperatures were related to : 1) leakage of minerals, and/or 2) the lack of formation or denaturation of proteins associated with germination and radicle elongation.
Technical Abstract: Suboptimal soil temperatures retard germination of cucumber (Cucumis sativus L.) seed leading to uneven stands and reduced yield. This project was undertaken to determine how mineral (N, NO2, NO3, P, PO4, K, SO4, Ca, Fe, Mg, Mn and Na) and protein concentrations changed during germination and radicle elongation in the cv's. 'Arkansas Little Leaf' and 'Earlipik 14'. Seed were incubated in distilled water in petri dishes at 13.9, 15.6, and 20 deg C. Seed were analyzed for mineral content and proteins prior to incubation and then at intervals up to 168 hr. At 20 deg C, at least 90% of seed of both cultivars germinated by 48 hr. The content of N, P, PO4, K, and SO4 'Earlipik 14' seed were significantly less at 13.9 or 15.6 than at 20 deg C. This suggests leakage of minerals occurred at suboptimal temperatures. After 24 hr incubation at 20 deg C the concentration of the 70.1 Kda protein did not increase, while concentrations of 37.4, 43.4, and 50 Kda proteins increased in seed of both cultivars. At the other temperatures concentrations of proteins increased until 120 hrs. The data suggests that low cucumber germination rates at suboptimal temperatures were related to: 1) leakage of minerals, and/or 2) the lack of formation of denaturation of proteins associated with germination and radicle elongation.