Abstract
ABSTRACT Fluorescence ratiometric imaging of Lilium pollen tubes loaded with the Ca2+ indicator Fura-2 dextran has revealed a distinct elevation of free intracellular calcium ion concentration ([Ca2+]i) at the extreme tip of actively growing Lilium pollen tubes that declines to a uniform basal level of ∼170 nM throughout the length of the tube. The calcium gradient occurs within the first 10–20 μM proximal to the tip. Experimental inhibition of tip growth, usually achieved through the injection of the Ca2+ buffer 5,5’-dibromo BAPTA, results in the loss of the [Ca2+]igradient. Occasionally these inhibited cells reinitiate growth, and when they do so ratio imaging reveals that the tip gradient of free [Ca2+Ji re-emerges. The results presented here are very different from those previously published by revealing the presence of the [Ca2+]i gradient that is restricted to the 10–20 μM adjacent to the tube tip. Further, these experiments demonstrate a strict correlation between the presence of a [Ca2+Ji gradient, and tip growth in Lilium pollen tubes.
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Claims 4
Claim · model-written summary
Growing Lilium pollen tubes had elevated tip calcium declining to a basal level.
- Organ / stage
- pollen tubese0
- Outcome
- free intracellular calcium ion concentratione0
- Direction
- declinese0
- Value
- ∼170 nMe0
LiliumOrganisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“a distinct elevation of free intracellular calcium ion concentration ([Ca2+]i) at the extreme tip of actively growing Lilium pollen tubes that declines to a uniform basal level of ∼170 nM throughout the length of the tube”
Claim · model-written summary
The calcium gradient lay within the first 10–20 μM from the tip.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“lilium”
e0“The calcium gradient occurs within the first 10–20 μM proximal to the tip.”
Claim · model-written summary
Inhibition of pollen-tube tip growth eliminated the calcium gradient.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“lilium”
e0“Experimental inhibition of tip growth, usually achieved through the injection of the Ca2+ buffer 5,5’-dibromo BAPTA, results in the loss of the [Ca2+]igradient.”
Claim · model-written summary
In inhibited cells that resumed growth, the tip calcium gradient re-emerged.
- Organ / stage
- tipe0
- Outcome
- tip gradient of free [Ca2+Jie0
- Direction
- re-emergese0
- Qualifier
- reinitiate growthe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“lilium”
e0“Occasionally these inhibited cells reinitiate growth, and when they do so ratio imaging reveals that the tip gradient of free [Ca2+Ji re-emerges.”
The same questions in other papers
application · nutrient: content · LiliumPositive and negative results
1 in the opposite direction
- positive
Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.