Seed chlorophyll content as an indicator for seed maturity and seed quality.

The production of good quality seed requires timely harvest at physiologica l maturity for maximal seed vigour. Until now, the maturity status of seeds could not be determined non-destructively Chlorophyll fluorescence (CF) is now adopted by the seed industry as a new technology that is applicable fo r effective characterisation of seed quality. Chlorophyll a in the seed coa t was excited by laser radiation (670 nm) and the resulting fluorescence wa s measured instantaneously and non-destructively. An exponential decrease i n CF during development and maturation of tomato (Lycopersicon esculentum M ill.) seeds was found. This decline in CF signal was directly related to th e germination performance under laboratory and greenhouse conditions. A sor ting apparatus based on the CF signal was developed for analysing and sorti ng seeds individually. Separating tomato seeds into six subsamples varying in CF signal resulted in an optimal seed quality (expressed as percentage o f normal seedlings) at intermediate CF signal. Seeds with high CF signal we re of lower quality and seeds with the lowest CF signal were of slightly lo wer quality. A seed sample of white cabbage (Brassica oleracea L.) was also sorted into six CF subsamples. The subsample with the highest CF intensity resulted in the lowest quality and the quality increased with decreasing C F signal. CF is both highly specific and sensitive for chlorophyll and CF m easurements can be used as a technique for analysing and sorting seeds of v arious plant species based on their maturity. Furthermore, CF opens new pos sibilities to better understand the relation between seed maturity and its physiological, phytopathological and physical aspects.