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> 俗话说“梨树砍三刀,树枝压弯腰”,其丰产的道理是()A.限制了水分和无机盐向根部运输B.防治了害虫的侵害C.限制了有机物向根部运输D.限制了水分和无机盐向茎叶运输-七年级生物
俗话说“梨树砍三刀,树枝压弯腰”,其丰产的道理是()A.限制了水分和无机盐向根部运输B.防治了害虫的侵害C.限制了有机物向根部运输D.限制了水分和无机盐向茎叶运输-七年级生物
题目简介
俗话说“梨树砍三刀,树枝压弯腰”,其丰产的道理是()A.限制了水分和无机盐向根部运输B.防治了害虫的侵害C.限制了有机物向根部运输D.限制了水分和无机盐向茎叶运输-七年级生物
题目详情
俗话说“梨树砍三刀,树枝压弯腰”,其丰产的道理是( )
A.限制了水分和无机盐向根部运输
B.防治了害虫的侵害
C.限制了有机物向根部运输
D.限制了水分和无机盐向茎叶运输
题型:单选题
难度:中档
来源:不详
答案
筛管是植物韧皮部(树皮内侧)内输导有机养料的管道.由许多管状活细胞上下连接而成.相邻两细胞的横壁上有许多小孔,称为“筛孔”.两细胞的原生质体通过筛孔彼此相通.筛管没有细胞核,但筛管是活细胞.果农常常给果树的茎做环状剥皮,有机物向下的运输通道筛管被割断,减少了叶片制造的有机物向下方根部的运输,能使有机物集中运输到果实,增加坐果量,提高产量.
故选C.
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题目简介
俗话说“梨树砍三刀,树枝压弯腰”,其丰产的道理是()A.限制了水分和无机盐向根部运输B.防治了害虫的侵害C.限制了有机物向根部运输D.限制了水分和无机盐向茎叶运输-七年级生物
题目详情
答案
故选C.