Stomatal frequency, size, and genetics of tossa jute (Corchorus olitorius L.). (149)
Keywords:Tossa jute, Stomata, Conductance, Diurnal variation, Genetics
AbstractIn an attempt to impart drought tolerance with improved photosynthetic efficiency in tossa jute (Corchorus olitorius L.), several stomatal characters including conductance, their diurnal variation, and inheritance were studied. Stomata of tossa jute are paracytic, amphistomatic, and anisostomatic. In the upper epidermis, stomata were larger than the lower epidermis which appeared to be due to variation in aperture length. Stomata were significantly (P < 0.01) more in the lower epidermis than those of the upper. In the lower leaf surface, stomata were randomly distributed, but in the upper surface the distribution was site specific (crowding near mid-vein). In the upper epidermis, higher stomatal spacing and lower stomatal conductance (pore area mm-2) were observed. The reverse was true for the lower epidermis. Stomatal movement over time differed between the two leaf surfaces. Differential genotypic variation in stomatal characters and diurnal variation were recorded. The outstanding variety JRO-632 maintained efficient gaseous exchange due to higher pore area per leaf which accounted for 2.5% of the total leaf. The genetics study following a six parameter model indicated different and complex genetic control for various stomatal characters in both leaf surfaces. More than one gene was involved. Additive x additive, additive x dominance, and dominance x dominance gene interactions as well duplicate epistasis were important.