Reproduction in plants can be limited by access to pollen and resources. We previously found that Echinacea plants in the remnants are pollen limited, meaning that if they had access to more pollen, they would produce more seeds. However, the long-term effects of pollen limitation are unknown. Do plants that are super pollen saturated and have high amounts of pollen have a higher lifetime fitness than plants that are pollen limited? Also, we know that the plants in the remnants are pollen limited, but are the plants in the common garden environment also pollen limited? To answer these questions and more, 10 years ago Gretel randomly selected 38 plants from experimental plot 1; half of these plants were randomly assigned to the pollen addition group, and the others were assigned to pollen exclusion. Every year, plants in the pollen exclusion have their heads bagged and they are not pollinated, while we hand cross every style in the pollen addition group (See photos for reference).
In the summer of 2022, 24 of the original 38 plants were found to be living. 6 plants of the addition group were flowering with a total of 17 heads. They received hand pollination throughout their flowering time. 6 plants of the exclusion group were flowering and they received pollinator exclusion bags to remain un-pollinated during their flowering time.
Start year: 2012
Location: exPt 1
Specimens collected: 64 heads were harvested from the addition, exclusion and control group in the 2022 field season.
Data collected: Plant survival and measurements were recorded as part of our annual surveys in P1 and eventually will be found in the R package EchinaceaLab. Data sheets were scanned and entered and can be found here: “~/Dropbox/CGData/115_pollenLimitation/pollenLimitation2022”
You can find more information about the pollen addition and exclusion experiment and links to previous flog posts regarding this experiment at the background page for the experiment.
A pollen exclusion plant with a pollinator exclusion net from the pollen exclusion group. These plants wear crowns 👑Sophia conducting hand pollination on one of the plants in the addition group.
Reproduction in plants can be limited by access to pollen and resources. We previously found that Echinacea plants in the remnants are pollen limited, meaning that if they had access to more pollen, they would produce more seeds. However, the long-term effects of pollen limitation are unknown. Do plants that are super pollen saturated and have high amounts of pollen have a higher lifetime fitness than plants that are pollen limited? Also, we know that the plants in the remnants are pollen limited, but are the plants in the common garden environment also pollen limited? To answer these questions and more, 13 years ago Gretel randomly selected __ plants from p1; half of these plants were randomly assigned to the pollen addition group, and the others were assigned to pollen exclusion. Every year, plants in the pollen exclusion have their heads bagged and they are not pollinated, while we hand cross every style in the pollen addition group.
In the summer of 2021, 23 of the original 39 plants were found to be basal. There were no flowering plants this year, so no crosses occurred.
Start year: 2012
Location: exPt1
Physical specimens: No heads were harvested in 2021.
Data collected: Plant survival and measurements were recorded as part of our annual surveys in P1 and eventually will be found in the R package EchinaceaLab. Data sheets were scanned and entered and can be found here: “~/Dropbox/CGData/115_pollenLimitation/pollenLimitation2021”
You can find more information about the pollen addition and exclusion experiment and links to previous flog posts regarding this experiment at the background page for the experiment.
Reproduction in plants can be limited by access to pollen and resources. We previously found that Echinacea plants in the remnants are pollen limited, meaning that if they had access to more pollen they would produce more seeds. However, the long-term effects of pollen limitation are unknown. Do plants that are super pollen saturated and have high amounts of pollen have a higher lifetime fitness than plants that are pollen limited? Also, we know that the plants in the remnants are pollen limited but are the plants in the common garden environment also pollen limited? To answer these questions and more 13 years ago Gretel randomly selected __ plants from p1 half of these plants were randomly assigned to the pollen addition group and the others were assigned to pollen exclusion. Every year, plants in the pollen exclusion have their heads bagged and they are not pollinate, where we hand cross every style in the pollen addition group.
In the summer of 2020, 27 of the original 39 plants were found to be alive 13 of the alive plants were in the pollen exclusion treatment and 14 were in the pollen addition treatment. There were nine plants that flowered, 5 were in the addition group with 12 heads, and 4 in the exclusion group with 6 heads.
Start year: 2012
Location: exPt1
Physical specimens: We harvested 18 heads, these heads are at CBG and have been inventoried and are waiting to be cleaned.
Data collected: Plants survival and measurements were recorded as part of our annual surveys in P1 and eventually will be found in the R package EchinaceaLab. Data sheets were scanned and entered and can be found here: “~/Dropbox/CGData/115_pollenLimitation/pollenLimitation2020”
You can find more information about the pollen addition and exclusion experiment and links to previous flog posts regarding this experiment at the background page for the experiment.
Supplemental pollen — pollen that an Echinacea head might not otherwise receive—could increase a plant’s fitness. But does this extra pollination lead to a tradeoff in survival or flowering consistency? Since 2012, we have been manipulating the amount of pollen Echinacea plants receive – either no pollen, or lots of pollen – and recording how this affects their fitness and survival. In 2012 and 2013 we identified flowering E. angustifolia plants in experimental plot 1 and randomly assigned one of two treatments to each: pollen addition or pollen exclusion. The team bagged the heads of all plants and hand-pollinated the addition treatment, and did not manipulate the exclusion plants further. Plants receive the same treatment across years.
In summer 2018, 14 of the 26 plants alive in the pollen addition and exclusion experiment flowered, producing a total of 25 heads. This year none of those plants flowered. Of the original 38 plants in this experiment, 12 of the exclusion plants and 14 of the pollen addition plants are still alive. No plants died between 2018 and 2019. This year’s data were unique among the eight years of data collected, because not a single plant in the experiment produced even a single head. The dramatic decrease in flowering rates this year may help or hinder us in analyzing this data set and providing answers to this eight-year question.
Tris did not find significant demographic differences between plants which received pollen exclusion, addition or open pollination treatments.
Start year: 2012
Location: exPt1
Physical specimens: We harvested no specimens this year
Data collected: Plants survival and measurements were recorded as part of our annual surveys in P1 and can be found with the rest of the P1 data in the R package EchinaceaLab.
Michael presented a poster on the polLim experiment at MEEC
2019, which you can find here
Tris also presented a poster on polLim at MEEC 2019, which you can find here
You can find more information about the pollen addition and
exclusion experiment and links to previous flog posts regarding this
experiment at the background page for the experiment.
Like Tris, I am also presenting work related to pollen limitation in Echinacea. For my project, I simply tried to find whether pollen limitation is present in Echinacea or not. What I found – it’s not (though, after presenting this poster, there has been some controversy!). It just seems that echinacea produces as much seed as it can up to a certain limit, then stops, regardless of whether more styles were pollinated.
I went a little unorthodox with the way I designed this poster. Instead of the normal “wall of text” design, I instead opted to use the “better poster” design created by Mike Morrison. I really liked using this! It was so incredibly easy to make, and it really facilitated great conversations with everyone who stopped by poster slot #37. I’m very much looking forward to using this poster design each and every time I present from now on.
Michael with his pollen limitation poster
Title: No evidence of pollen limitation in the long-lived perennial Echinacea angustifolia
Presented at: MEEC 2019 at Indiana State University in Terre Haute, IN
I’m back with more updates from our team trip to Terre Haute for MEEC 2019. Today, I want to show off the incredible pollen limitation study poster presented by Tris Dodge. Tris joined Team echinacea this last November when he was a Carleton Extern at the Chicago Botanic Garden for three weeks before winter break. As an intern, Tris did a lot of work gathering and analyzing data on our pollen limitation study. If you want to learn more about that study, check out our background page. If you want to see the work that Tris did specifically, check out the flog posts that he has written. Tris’s flog posts include a direct link to his poster
In his analysis, Tris found out that creating seeds is basically free for echinacea plants. If they produce a lot of seeds one year, they can produce a lot of seeds the next year as well. This was not what we had predicted! Tris used the data from 7 years of the pollen limitation study to show that plants that had zero reproduction did not turn into big-leafed, multi-head super plants, but instead look exactly the same as those heads that produced many achenes.
Tris presenting his poster to Nate
Title: Little cost of reproduction in the long lived perennial, Echinacea angustifolia
Presented at: MEEC 2019 at Indiana State University in Terre Haute, IN
Michael adds pollen to one of the “addition” plants using a toothpick and a vial of collected pollen.
Does receiving the maximum amount of pollination vs. no pollen at all affect a plant’s longevity or likelihood of flowering in subsequent years? Since 2012, we have been either adding or excluding pollen from the same plants’ heads to test what role pollen plays in ongoing survival and flowering. Unlike the previous two years, many plants in this experiment flowered this year, and analyzing them will likely reveal interesting results.
This summer, 14 of the 26 plants remaining in the pollen addition and exclusion experiment flowered, for a total of 25 heads. This is the most heads the pollen addition and exclusion project has had since 2013. We continued experimental treatments on these flowering plants and recorded the survival and flowering status of all plants in the experiment. Of the original 38 plants in this experiment, 12 of the exclusion plants and 14 of the pollen addition plants are still alive.
In this experiment, we assess the long-term effects of pollen addition and exclusion on plant fitness. In 2012 and 2013 we identified flowering E. angustifolia plants in experimental plot 1 and randomly assigned one of two treatments to each: pollen addition or pollen exclusion. When plants flower in subsequent years they receive the same treatment they were originally assigned. The increase in flowering rates this year will allow us to move forward with analyzing this data set, to potentially answer this 7-year question.
Start year: 2012
Location: Experimental plot 1
Physical specimens: We harvested 25 flowering heads from this experiment that will be pulled from the normal ACE processing and pushed through faster. This is so we can more quickly determine achene count and proportion of full achenes.
Data collected: Plants survival and flowering data was recorded as part of our annual surveys in P1 and can be found with the rest of the P1 data. Data on when heads had pollen added can be found in CGData/115_pollenLimitation, particularly dailyPollenAddition for the year 2018.
You can find more information about the pollen addition and exclusion experiment and links to previous flog posts regarding this experiment at the background page for the experiment.
Wow! These last three weeks passed by super quickly! While the first two weeks were focused on seed cleaning, seed counting, and x-raying, we spent this past week on our independent projects. But that’s not to say this week was easy! In the past 5 days, I wrote exactly 900 lines of code in R to generate the figures and perform the analyses.
To get at how current pollen limitation affects Echinacea growth and future fitness, I performed analyses testing differences in plant traits between pollen exclusion, pollen addition, and open pollination treatments. I did not find evidence that pollination treatment affected either growth or fitness, which indicates that current pollen limitation will not benefit Echinacea in the future. This could be because Echinacea is not resource limited or because the cost of seed production is negligible.
Many thanks to the members of Team Echinacea who helped guide me through this process and made working in the lab such a pleasure!
Does receiving the maximum amount of pollination vs. no pollen at all affect a plant’s longevity or likelihood of flowering in subsequent years? We are trying to find out in this long-term experiment, but flowering rates have been so low in the past few years we are not learning much.
This summer, only three plants flowered of the 27 plants remaining in the pollen addition and exclusion experiment. We continued experimental treatments on these flowering plants and recorded fitness characteristics of all plants in the experiment. Of the original 38 plants in this experiment, 13 of the exclusion plants and 14 of the pollen addition plants are still alive.
In this experiment we assess the long-term effects of pollen addition and exclusion on plant fitness. In 2012 and 2013 we identified flowering E. angustifolia plants in experimental plot 1 and randomly assigned one of two treatments to each: pollen addition or pollen exclusion. When plants flower in subsequent years they receive the same treatment they were originally assigned. Because flowering rates have been so low in 2016 & 2017, differences in flowering due to treatment are not detectable.
Start year: 2012
Location: Experimental plot 1
Physical specimens: We harvested three flowering heads from this experiment that will be processed with the rest of the experimental plot 1 heads to determine achene count and proportion of full achenes.
Data collected: We recorded data electronically as part of the overall assessment of plant fitness in experimental plot 1. We recorded dates of bagging heads and pollen addition on paper datasheets.
You can find more information about the pollen addition and exclusion experiment and links to previous flog posts regarding this experiment at the background page for the experiment.
We observed that 95% surviving members of the 1996 cohort were basal in 2016
Does receiving the maximum amount of pollination vs. no pollen at all affect a plant’s longevity or likelihood of flowering in subsequent years? In this experiment we assess the long-term effects of pollen addition and exclusion on plant fitness. In 2012 and 2013 we identified flowering E. angustifolia plants in experimental plot 1 and randomly assigned one of two treatments to each: pollen addition or pollen exclusion. When plants flower in subsequent years they receive the same treatment they were originally assigned.
Across all experiments, 2016 was a low flowering year. Only four plants flowered of the 29 plants remaining in the pollen addition and exclusion experiment. We continued experimental treatments on these plants and recorded fitness characteristics.
Start year: 2012
Location: Experimental plot 1
Physical specimens: We harvested four flowering heads from this experiment that will be processed with the rest of the experimental plot 1 heads to determine achene count and proportion of full achenes. The labels for these heads, beginning with the letter “p,” identify them as part of the pollen addition and exclusion experiment.
Data collected: We recorded data electronically as part of the overall assessment of plant fitness in experimental plot 1. We recorded dates of bagging heads and pollen addition on paper datasheets.
You can find more information about the pollen addition and exclusion experiment and links to previous flog posts regarding this experiment at the background page for the experiment.
