主叶脉 meaning in Chinese

rib

May appear variegated with mottled pattern over main veins . usually upright single crown , rarely suckers . standard
有时在主叶脉有斑叶的花样。通常单个顶芽，很少有侧芽。标准型。
In comparison with ck , obvious morphological variation were observed in the transgenic tobaccos . their leaves became greener and thicker , chief veins turned bolder and thicker than those of ck
与对照相比转基因烟草在形态上发生了明显的改变：叶片颜色变深绿；叶片增厚；主叶脉变粗壮等。
Foliage usually dark green ( or sometimes faded ) with dark brown or black necrotic spotting along major leaflet veins often appearing first on under surfaces and also along petiole ; profuse black spotting an sometimes black streaks along stems ) ( “ stem streak necrosis ” )
马铃薯锰中毒：叶片通常深绿（有时褪色），深褐色或黑色坏死斑点首先出现在表面内沿着主叶脉一直到叶柄，大量黑色斑点有时沿着茎连成一条黑色条纹（ “茎条纹病” ）。