
%0 Journal Article
%A Kallarackal, J 
%A Milburn, JA 
%T Studies on the Phloem Sealing Mechanism in <I>Ricinus</I> Fruit Stalks
%J Functional Plant Biology
%D 1983/12/01
%V 10
%N 6
%P 561-568
%K 
%R https://doi.org/10.1071/PP9830561
%U https://www.publish.csiro.au/paper/PP9830561 
%X Fruit stalks of R. communis were made to exude phloem sap by repeated slicing at intervals of a few minutes. Samples 1 mm thick from the fruit stalks were fixed for electron microscopy. Samples were also fixed and processed for electron microscopy from previously intact (non-exuding) fruit stalks. Examination of the sieve tubes from these two different samples showed predominantly open sieve-plate pores in the exuding fruit stalk. The sieve plates of the non-exuding fruit stalk showed occlusion of the sieve-plate pores by P-protein. The starch grains from the broken plastids also had characteristic distributions. The implications of these observations are discussed in relation to comprehending the mechanism by which sieve-plate pores become choked, and so sealing the sieve-tube system as a result of injury. 
