Kholupenko I.P., Burundukova O.L., Zhemchugova V.P., Voronkova N.M., Tchernoded G.K.
В журнале Russian Journal of Plant Physiology
Год: 1996 Том: 43 Номер: 2 Страницы: 165-173
Two old and two new rice (Oryza saliva L.) cultivars differing in their morphological characteristics and source-sink relations were compared with respect to leaf area and structure, the rate of carbon dioxide assimilation by the flag leaf, and the interorgan partitioning of radioactive assimilates on the seventh day after flowering, i.e., in the early grain-filling phase. In addition, time patterns of dry matter production in rice organs, potential productivity, seed production, and yield quality were compared. By the seventh day after flowering, the new cultivars developed double the number of grains per 1 dm2 leaf area as compared to the old cultivars. The weight of the vegetative organs decreased in the period between the 7th and 23rd days after flowering, although no shedding occurred. New cultivars were characterized by smaller leaf area, less assimilate deposition in the vegetative organs in the early grain-filling phase, earlier utilization of the assimilates temporarily stored in the vegetative organs, slower grain filling, higher potential productivity, and an increased fraction of shrunk grains and seedless spikelets. In 1987, the cultivars did not differ in the bulk grain yield and the proportion of conditioned, filled grains. In 1988, the yield of all cultivars was higher, and new cultivars showed a relatively higher grain yield. It is reasoned that the new cultivars are characterized by too great a sink demand on the source leaves. Further increase in the grain number without concurrent increase in the area of the leaves remaining on the plant by the early grain-filling phase is not advisable.
