UNLABELLED • PREMISE OF THE STUDY Variation in how seeds are dispersed in grasses is ecologically important, and selection for dispersal mechanisms has produced a great variety of dispersal structures (diaspores). Abscission ("shattering") is necessary in wild grasses, but its elimination by selection on nonshattering mutants was a key component of the domestication syndrome in cereal grasses...

The objective of this year's work was to confirm the role of pollen in pistillate flower abscission (PFA) of Serr walnut. Pistillate flower abscission was evaluated in individual trees along transects, beginning close to po11enizers and extending up to 640 feet away, in 12 orchards. It was also evaluated in controlled pollinations of bagged and unbagged Serr flowers with varying levels of Serr ...

Longkong (Lansium domesticum) fruit grows in bunches and is also sold as bunches. Individual fruit can separate from the bunch both before and after commercial harvest. The fruit has two separation sites. The first is located between bracts on the stem and the fused sepals (separation zone 1: SZ1) and the second between the fused sepals and the fruit (separation zone 2: SZ2). True abscission oc...

The effects of Silver Thiosulphate (STS) and Naphtalene Acetic Acid (NAA) (0,45%NAA+1,2% NAA-amide at 500 mg.l) on flowering bud development, anthesis duration, bract longevity and bract photosynthetic rate were studied in Bougainvillea spectabilis ‘Killie Campbell’ plants, under interior conditions. The relationships between bract longevity and the above parameters were also investigated. NAA ...

The small GTPase RhoA plays a crucial role in the different stages of cytokinesis, including contractile ring formation, cleavage furrow ingression, and midbody abscission. Citron kinase (CIT-K), a protein required for cytokinesis and conserved from insects to mammals, is currently considered a cytokinesis-specific effector of active RhoA. In agreement with previous observations, we show here t...

Seedlings of tomato fruit ripening mutants were screened for their ability to respond to ethylene. Ethylene induced the triple response in etiolated hypocotyls of all tomato ripening mutants tested except for one, Never ripe (Nr). Our results indicated that the lack of ripening in this mutant is caused by ethylene insensitivity. Segregation analysis indicated that Nr-associated ethylene insensi...

A fast neutron-mutagenized population of Arabidopsis (Arabidopsis thaliana) Columbia-0 wild-type plants was screened for floral phenotypes and a novel mutant, termed hawaiian skirt (hws), was identified that failed to shed its reproductive organs. The mutation is the consequence of a 28 bp deletion that introduces a premature amber termination codon into the open reading frame of a putative F-b...

The tomato (Lycopersicon esculentum cv Ailsa Craig) polygalacturonase genes TAPG1 (LYCes;Pga1;2) and TAPG4 (LYCes;Pga1;5) are abundantly expressed in both abscission zones and the pistils of mature flowers. To further investigate the spatial and temporal expression patterns for these genes, the TAPG gene promoters were ligated to beta-glucuronidase (GUS) reporter genes and transformed into toma...