scholarly journals The Use of Fluorescent Tracers to Characterize the Post-Phloem Transport Pathway in Maternal Tissues of Developing Wheat Grains

1994 ◽  
Vol 104 (1) ◽  
pp. 17-27 ◽  
Author(s):  
N. Wang ◽  
D. B. Fisher
Keyword(s):  
Phloem Transport ◽  
Fluorescent Tracers ◽  
Transport Pathway ◽  
Wheat Grains

scholarly journals Phloem transport limitation in Huanglongbing affected sweet orange is dependent on phloem-limited bacteria and callose

2021 ◽  
Author(s):  
Stacey Welker ◽  
Myrtho Pierre ◽  
James Patrick Santiago ◽  
Manjul Dutt ◽  
Christopher Vincent ◽  
...  
Keyword(s):  
Genetic Material ◽  
Sugar Transport ◽  
Phloem Transport ◽  
Microbial Infection ◽  
Transport Pathway ◽  
Callose Deposition ◽  
Citrus Production ◽  
Candidatus Liberibacter ◽  
Phloem Translocation ◽  
Translocation Speed

Huanglongbing (HLB), caused by Candidatus Liberibacter asiaticus (CLas), is a phloem-limited disease which disrupts citrus production in affected areas. In HLB-affected plants, phloem sieve plate pores accumulate callose, and leaf carbohydrate export is reduced. However, whether HLB causes a reduction in carbohydrate phloem translocation speed, and the quantitative relationships among callose, CLas population, and phloem translocation are still unknown. In this work, a procedure was developed to concurrently measure sugar transport, callose deposition, and relative pathogen population at different locations throughout the stem. Increasing quantities of CLas genetic material were positively correlated with quantity and density of callose deposits, and negatively correlated with phloem translocation speed. Callose deposit quantity was site- and rootstock dependent, and were negatively correlated with phloem translocation speed, suggesting a localized relationship. Remarkably, callose accumulation and phloem translocation disruption in the scion was dependent on rootstock genotype. Regression results suggested that the interaction of Ct values and number of phloem callose depositions, but not their size or density, explained the effects on translocation speed. Sucrose, starch, and sink 14C label allocation data support the interpretation of a transport pathway limitation by CLas infection. This work shows that the interaction of local accumulation of callose and CLas affect phloem transport. Further, the extent of this accumulation is attenuated by the rootstock and provides important information about the disease mechanism of phloem-inhabiting bacteria. Together, these results constitute the first example of a demonstrated transport limitation of phloem function by a microbial infection.

Transport of zinc and manganese to developing wheat grains

1995 ◽  
Vol 95 (3) ◽  
pp. 449-455 ◽  
Author(s):  
J. N. Pearson ◽  
Z. Rengel ◽  
C. F Jenner ◽  
R. D. Graham
Keyword(s):  
Wheat Grains
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