大麦表皮蜡质组分及晶体结构的差异性分析

Analysis on Cuticular Wax Components and Crystal Structures of Different Barley Varieties(Lines)

为了解不同大麦品种(系)表皮蜡质组分及结构的差异,以7个大麦品种(系)开花期的倒二叶、穗下节及穗为材料,利用GC-MS和S-4800场发射扫描电子显微镜测定不同器官表皮蜡质组分,观察其晶体结构。结果表明,大麦不同器官表皮蜡质均是由烷烃、初级醇、醛、脂肪酸、二酮等20种物质组成,不同品种及不同器官表皮蜡质组分种类无明显差异,但组分含量差异显著;同一品种(系),表面有白霜覆盖器官蜡质总量明显高于无白霜覆盖器官。穗下节表皮蜡质及穗部白霜型品种(系)表皮蜡质的二酮含量最高,穗部无白霜品种(系)(QS、FR、SYR01)表皮蜡质以烷烃和初级醇为主,二酮含量显著低于白霜型品种;叶片表皮蜡质则以初级醇为主,含量明显高于其他组分,且品种(系)间差异显著。电镜观察结果表明,参试品种(系)倒二叶近轴面和远轴面表皮蜡质晶体均呈片状结构;穗下节表皮蜡质晶体结构均呈棒状,SYR01穗下节蜡质晶体附着密度远小于其余6个穗下节有白霜覆盖品种(系)。白霜型大麦品种(系)穗部表皮蜡质完全为棒状,非白霜型品种(系)穗部表面仅有少量片状蜡质晶体或无蜡质晶体附着。

In order to understand the differences of cuticular wax components and crystal structures of different barley varieties(lines),we detected the cuticular wax components of peduncle,spike and top second leaf in seven barley varieties(lines)at anthesis using gas chromatography-mass spectrometry(GC-MS),and observed wax crystal structures of different organs by scanning electron microscope(S-4800).The results showed that cuticular wax on different organs in the seven barley varieties(lines)contained 20 compounds,including alkanes,alcohols,aldehydes,fatty acids and diketones.There was no obvious difference in wax composition among different organs of the seven barley varieties(lines),but the contents of each component and total wax were significantly different.Among the seven barley varieties(lines),the total wax on glaucous organs were significantly higher than that on glossy organs,among which the content of diketones was the highest on glaucous stems and spikes,but the epicuticular wax on glossy spikes(QS,FR SYR01)was mainly composed of alkanes and primary alcohols,and contained very little diketones,which were significantly less than those on the glaucous spikes.The main component of leaf epicuticular wax was primary alcohol,whose content was much higher than other components,and there were significant differences among different barley varieties(lines).The wax crystal structure on abaxial and adaxial surface of the top second leaf was platelet-shaped structure;the stem wax crystal structure was rod-shaped,and the covering density of the wax crystals on the stem of SYR01 was much lower than that of glaucous stem.The wax crystal structures with rods generally exist on glaucous spikes of the seven barley varieties(lines),but the surfaces of glossy spikes were only covered with a few platelet-shaped crystals or no wax crystal.