【摘要】 以光合强度高,对光反应迟钝的729和株型优良,对光反应敏感的南粳35为主要亲本进行杂交。在F₄的分离群体中,经低（CO₂）空气筛选出高净光合材料,置于弱光下生长。根据不同光强下的形态、生理指标鉴定,可分辨出避阴和耐阴两种光合生态型。高产育种应选耐阴型。这种类型由强光转到弱光条件下,茎叶生长速度较慢,气孔反应迟钝,净光合强度下降较少,叶绿体光化学还原特性变化较稳定,对变化光强表现广泛的适应性。这些系列特性表明,耐阴型栽培在不同生态地区,在变动光强和高产群体叶片相互遮阴条件下,具有株高、叶型稳定和光合器有较高工作效率的特点。试验证明,这种生理特性是遗传的。更多还原

【Abstract】 In this paper, a screening and identification technique is presented for sorting out variants with high photosynthetic rates adapted to a wide range of light intensity from F4 segregating populations which came from crosses between light-sensitive and insensitive rice varieties.The screening technique consisted of 2 steps. The rice seedlings were first screened in an illuminated hermetic chamber with lower CO2 concentration created by growing a C4plant (Pennisetum purpureum) together with the rice seedlings (C3 plant) for 5-7 days to select the tolerant ones. Then further screening was undertaken under lower light intensity (1/3 of full sunshine) for 14 days to select the desirable plants by their morphological and physiological indexes related to photosynthesis.In that way, two photosynthetic ecotypes were distinguished: the shade-avoiding type and shade-tolerant type. The former was characterized by elongation of leaves competing for light, quicker response of stomatal action and a sharp drop of photosynthetic activity under lower light intensity, while the later was characterized by an apparent decrease of specific leaf weight(SLW), slow response of stomatal action to light intensity changes and relative stability of photosynthetic activity.It was assumed that the photosynthetic apparatus of the shade-tolerant type might be more useful in increasing photosynthetic efficiency for a high-yielding crop com-unity which was always heavily shaded by the overlapping leaves in the crop profile.更多还原