Characterization of leaf starch from HLB-affected and unaffected-girdled citrus trees
Characterization of leaf starch from HLB-affected and unaffected-girdled citrus trees
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DOI：
10.1016/j.pmpp.2012.05.002
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发表时间：
2012-07-01
影响因子：
2.7
通讯作者：
Etxeberria, Ed
中科院分区：
文献类型：
--
作者：
Gonzalez, Pedro;Reyes-De-Corcuera, Jose;Etxeberria, Ed
与非HLB树相比，受HLB（黄龙病或柑橘绿化）影响的枝条叶片中的淀粉含量急剧增加。淀粉不仅在光合细胞中过度积累，而且在维管薄壁组织和筛分子中也变得突出。这些观察意味着强烈的干扰淀粉代谢和同化物分配在HLB影响的树木。基于淀粉含量的升高，外观的淀粉颗粒在韧皮部元素，和以前的报道的病原体对淀粉特性的影响，我们假设，从HLB影响柑橘树的淀粉可能不同形态，物理和/或化学淀粉积累在其他健康的叶子。为了从健康的树中获得与受HLB影响的树的大小相当的淀粉颗粒，我们将2岁的树枝环绕并使淀粉积累3个月。利用明场、偏光和扫描电镜研究了淀粉的形态。HLB诱导的淀粉粒在大小、形状和整体外观上与环带枝没有形态学差异。当与2%I-2反应时，全淀粉级分的吸收光谱无显著差异（λ（max）分别为HLB 604.1和环化606.2nm; n = 6; p
Starch content in leaves of HLB (Huanglongbing or citrus greening)-affected branches increases sharply compared to those from non-HLB trees. Starch not only over-accumulates in photosynthetic cells, but starch grains become prominent in vascular parenchyma and sieve elements as well. These observations imply strong disturbances in starch metabolism and photoassimilate partitioning in HLB-affected trees. Based on the elevated starch content, appearance of starch granules in phloem elements, and previous reports of the pathogen effect on starch properties, we hypothesized that starch from HLB-affected citrus trees may differ morphologically, physically and/or chemically from starch accumulated in otherwise healthy leaves. To obtain starch granules from healthy trees of comparable size to those of HLB-affected trees, we girdled 2-year-old branches and allowed starch to accumulate for 3 months. Starch morphology was investigated under brightfield, polarized light and SEM. HLB-induced starch grains were not morphologically different in size, shape and overall appearance from those of girdled branches. When reacted with 2% I-2, no significant difference was observed in the absorption spectra of whole starch fractions (lambda(max) for HLB 604.1 and girdled 606.2 nm, respectively; n = 6; p