Haemoglobin is the protein that carries oxygen in blood and the team say plant and human versions are very similar.
They are looking at whether they can repackage the plant protein in a way that can be accepted by human tissue.
Scientists said this could be in three years. One UK expert said the study was “exciting” but a “long-term prospect”.
Blood transfusions can help many people in emergency situations who have lost a lot of blood and also those needing long-term treatments, such as for cancer and blood diseases.
Work by scientists at Lund University built upon an earlier studypublished in the journal Plant & Cell Physiology that found haemoglobin had an important role in plant development.
Sugar beet is grown commercially for sugar production.
Nelida Leiva at Lund University, who led the study, said the plant haemoglobin shared 50-60% similarity with the kind found in human blood but was more robust.
She said her work raised two possibilities – potentially adapting plant haemoglobin for use in humans and looking at using plants as a way of producing human haemoglobin.
Prof Leif Bulow at Lund University, who also worked on the study, said: “There is an enormous shortage of blood. We have to find some alternatives.”
‘Good, rigorous science’
The plant haemoglobin behaved similarly to a version found in the human brain and had a similar structure, he said.
The next step would be to develop the haemoglobin to see if it could be accepted by guinea pig and then human tissue, which could happen in three years.
Prof Denis Murphy, head of genomics and computational biology at the University of South Wales, told the BBC: “The study is good, rigorous science and describes an exciting finding.
“Although we have known for several decades that plants produce haemoglobin-like proteins, this study shows they are more common and are involved in more physiological processes that we thought before.”
But he said the idea of using the plant protein to substitute for human haemoglobin was speculative and would be a long-term prospect.