巨峰葡萄果实不同发育期维管束水分运输变化

Changes of Water Transportation in Berry Vascular Bundle at Different Developmental Phases of Kyoho Grape Berry

【目的】通过研究葡萄果实生长规律、果实硬度和膨压的变化、维管束结构和水分运输变化,揭示葡萄果实不同发育期维管束水分运输变化与果实生长间的关系。【方法】以4年生巨峰葡萄为材料,采用质外体染料示踪法研究葡萄果实不同发育期果实维管束水分运输变化。【结果】在第1次快速生长期(Phase I),果实生长迅速,果实硬度和果实膨压最大,果实周缘维管束被染色数量最多,染色范围最广,染料溶液在葡萄果实中的运输速率也最高,为0.97 cm.h-1;进入生长停滞期(Phase II),葡萄果实中的周缘维管束被染色数目减少,染料溶液在周缘维管束和中央维管束运输速率急剧下降,分别为0.08 cm.h-1和0.72 cm.h-1;在果实的第2次快速生长期(PhaseIII),果实硬度达到最低,膨压下降,染料溶液在果实中的运输速率比生长停滞期有所增加,但仍低于第1次快速生长期。通过对维管束解剖结构观察可以看出,葡萄进入转色期后,葡萄果实维管束木质部导管壁模糊,甚至瓦解。【结论】葡萄进入第2次快速生长期(Phase III)后,由于葡萄果实维管束中部分木质部结构瓦解、功能丧失,导致水分运输效率迅速下降,而该时期果实糖分积累增加,有利于提高果实渗透调节能力,促使水分通过韧皮部进入果实,从而促进果实第2次膨大生长。

[ Objective ] The objective of the experiment is to understand the relation ship between water transportation in berry vascular and berry growth. [Method] The berry growth, berry firmness and turgor, the structure of vascular bundle and water transportation in vascular bundle were studied. Apoplastic dye stuff was used as the tracer to study the water transportation in berry vascular. [Result] The results showed that during phase Ⅰ, the dorsal and central vascular bundles were colored mostly, the speeds of dye stuff transport in dorsal vascular bundles were the highest among three phases of berry development, the speed was 0.97 cm.hz. After phase Ⅱ, the distribution of dye stuff decreased, the speeds of dye stuff transport decreased, the speeds in dorsal and central vascular bundles were 0.08 cm.hl and 0.72 cm·h^-1, respectively. During phase Ⅲ, the distribution of dye stuff was still lower than phase Ⅰ. After phase Ⅱ, the walls of xylem vessels were indistinct, some of them were broken. [ Conclusion ] After phase Ⅲ, although the collapse of partial xylem structure and non-functional xylem led to the decrease in efficiency of water transportation in vascular, sugar accumulation in grape berry increased, osmoregulation in berry also increased, water entered into grape berry via phloem. These adjustments promoted the second rapid growth of grape berry.