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为明确白菜型冬油菜在冬前低温下叶片结构特征、光合作用特性及其抗寒性,本研究在0℃和–7.6℃自然低温条件下,选用白菜型冬油菜品种陇油7号(超强抗寒)和天油4号(弱抗寒),测定并比较其叶片气孔性状、解剖结构和光合、荧光参数的日变化等指标。结果表明,随着冬前温度下降,2个白菜型冬油菜叶片气孔密度、气孔面积、气孔周长、栅栏组织和海绵组织厚度均变小,细胞间隙变大,叶片变薄;P_n日变化呈“单峰”型曲线,无光合“午休”现象;叶片的P_n、G_s、T_r和CE均降低,而C_i均升高,说明是非气孔限制引起P_n降低。白菜型冬油菜在冬前低温条件下发生了光抑制现象,表现为F_m和F_v/F_m下降,F_o上升。与超强抗寒品种陇油7号相比,弱抗寒品种天油4号叶片气孔密度和气孔面积均较大,气孔总周长较长,叶片较厚,P_n、F_m和F_v/F_m均较高,说明冬前低温条件下,天油4号光合能力较强,光抑制程度较弱。白菜型冬油菜在冬前低温条件下的叶片气孔密度越大、气孔面积越大、气孔周长越长、叶片及栅栏组织和海绵组织越厚,光合能力越强,地上部生长越旺盛,品种抗寒性越差。本研究为冬油菜抗寒种质创新和育种提供了部分理论支撑。
In order to clarify the leaf structure, photosynthesis characteristics and cold resistance of Brassica campestris var. Chinensis at low temperature in winter before, under the conditions of natural low temperature of 0 ℃ and -7.6 ℃, we selected Brassica campestris var. Strong cold resistance) and Tianyou 4 (weak cold resistance). The leaf stomatal traits, anatomical structure, photosynthesis and diurnal changes of fluorescence parameters were measured and compared. The results showed that the leaf stomatal density, stoma area, stomatal length, palisade tissue and sponge tissue thickness decreased with the decrease of temperature before winter, and the intercellular space became larger and the leaf became thinner. The diurnal variation of P_n “Unimodal ” curve, no photosynthesis “lunch break ” phenomenon; leaves P_n, G_s, T_r and CE decreased, while C_i increased, indicating non-stomatal limitation caused P_n reduction. The photoinhibition phenomenon occurred in the cabbage-type winter rape under the pre-winter low temperature, which showed that F_m and F_v / F_m decreased and F_o increased. Compared with the super cold-resistant variety Longyou 7, the weak cold-resistant varieties Tianyou 4 had larger stomatal density and stomatal area, longer stomatal length and thicker leaves, P_n, Fm and Fv / Fm Higher, indicating that low temperature before winter, Tianyou 4 photosynthetic ability, light inhibition is weak. The results showed that the higher the stomatal density was, the larger the stomatal area was, the longer the stomatal length was. The thicker the leaf and palisade tissue and spongy tissue, the stronger the photosynthetic ability was, The worse sex. This study provided some theoretical support for the innovation and breeding of winter rapeseed cold-resistant germplasm.