Xylem plugging and postharvest longevity of cut Acacia holosericea

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dc.contributor.author K. Ratnayake
dc.contributor.author D.C. Joyce
dc.contributor.author R.I. Webb
dc.date.accessioned 2021-07-27T05:15:00Z
dc.date.available 2021-07-27T05:15:00Z
dc.date.issued 2015
dc.identifier.uri http://repository.wyb.ac.lk/handle/1/3484
dc.description.abstract An inherently short vase life is a problematic characteristic of cut flowers and foliage for otherwise attractive native Australian Acacia spp. Reasons underlying the poor postharvest water uptake of cut acacia stems have been elusive. A. holosericea was used to investigate possible bacteria-induced and wound-induced xylem occlusion. The effects of bacterial- and wound-induced xylem blockage on water uptake were investigated by light and scanning and transmission electron microscopy. Observations were made on cut stems that stood into either deionised water (DIW; control) or 0.5 mM Cu2+ solution and on stems pulsed with 2.2 mM Cu2+ solution and then stood into DIW. The stem-end region of cut A. holosericea that stood into DIW or Cu2+ solution became covered with bacterial growth after 3 days. Regardless of the bacterial biofilm, the Cu2+ treated stems had improved water relations and vase life. Therefore, the biofilm had little or no effect on cut A. holosericea longevity. Further observations revealed presence of a vessel-occluding substance (gel) originating from axial parenchyma cells in direct physical contact with xylem vessels. The gel exuded into vessel lumens through pit membranes, evidently as a wound-response. Xylem occlusion by gels in A. holosericea may be especially problematic due to an abundance of secretory contact cells relative to xylem elements. Nonetheless, active wound response processes may be the key determinant of short postharvest longevity for this and possibly other cut Acacia spp. Cu2+ treatments, however, disrupted the secretory function of axial parenchyma cells thereby preventing vessel occlusion by the gels. en_US
dc.language.iso en en_US
dc.publisher Proc. Int. Symp. on Ornamental Horticulture in the Global Greenhouse en_US
dc.subject acacia en_US
dc.subject cut foliage en_US
dc.subject copper en_US
dc.subject electron microscopy en_US
dc.subject gel en_US
dc.subject vase life en_US
dc.subject water uptake en_US
dc.title Xylem plugging and postharvest longevity of cut Acacia holosericea en_US
dc.type Article en_US


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