Abstract
Respiratory and photosynthetic rates of seven cytoplasm substitution lines of a common wheat were investigated. The cytoplasm substitution lines used were (umbellulata)-, (squarrosa)-, (speltoides)-, (dicoccoides)-, (cylindrica)-, (biuncialis)-, and (ovata)-CS. The investigation was conducted in four replications with each of the outdoor-and greenhouse-grown plants. In each replication, the first completely developed leaves of fifty seedlings were used for measuring respiratory and photosynthetic rates with an infra-red gas analyser. The first two leaves of other seedlings were used for an estimation of chlorophyll content. The results obtained are summarized as follows:
(1) The umbellulata and biuncialis cytoplasms depressed the leaf development; thus both respiratory and photosynthetic rates per leaf became lower, though the efficiency in respiration and photosynthesis was higher. They also caused retardation in attaining maximum photosynthetic rate.
(2) The squarrosa, speltoides, dicoccoides and cylindrica cytoplasms caused vigorous development of the first leaf. No other consistent effect was detected with them.
(3) The ovata cytoplasm depressed the first leaf development, and caused the retardation in attaining maximum photosynthetic rate in plants grown outdoors. No effect on both respiratory and photosynthetic rates was observed.
The results clearly showed that there is cytoplasmic control of respiration and photosynthesis. The present results also agreed with the classification of plasma types by Tsunewaki et al. (1976a). The phylogenetic significance of this grouping was discussed.
