Phoenix dactylifera

Tamara Bonnemaison launches a BPotD series with today’s entry. She writes:

We kick off a series about exceptional seeds with the story of a 2000 year old Phoenix dactylifera seed that was successfully germinated. Thank you to 3Point141@Flickr for submitting this lovely photo of a plant in the cultivated Medjool Group of Phoenix dactylifera. This photo was taken at Excalibur Fruit Trees Nursery in Florida, USA.

Phoenix dactylifera, or the “true” date palm, has played an important role for thousands of years of human history. In 1963, a stash of seeds “dating” (sorry, couldn’t help myself) from AD 70 was discovered in Masada, a fortress in present-day Israel. In 2005, Sarah Sallon of the Hadassah Medical Organization managed to germinate just one of the ancient date seeds, and that seedling has now grown into a palm tree called “Methuselah”. Date palms are dioecious, and it had been hoped that Methuselah would turn out to be female and produce fruit. Unfortunately, this date palm plant is now known to be male, and Sallon and her team will need to undertake careful breeding with modern date palms to produce females that are as close as possible to the ancient cultivated variety. Learn more about Masada and the discovery of these seeds from this National Geographic article: “Methuselah” Tree Grew From 2,000-Year-Old Seed.

The date palm is a 15-25m tall plant that is perhaps native to western India or southern Iraq, but a long history of use and cultivation has made it difficult for botanists to determine its exact place of origin. The fruit of Phoenix dactylifera is likely well known to all BPotD readers; this fruit was cultivated as a staple food and even to make date wine as early as 4000 BCE, and is still commonly eaten today (mmmmm, date squares). Other parts of the date palm may not be as sweet, but are equally useful. For example, palm hearts are used as a vegetable, the fibres can be woven to make a textile, the leaves are used to make mats, and the seeds produce a nutritious oil. For a more comprehensive list, view the Food and Agriculture Organization’s Date Palm Products bulletin.

Although the date palm can be wind-pollinated, the standard practice in cultivation is to hand-pollinate the flowers The flowers are borne at the top of the tree and covered by a protective spathe that splits open when the flowers are mature. The fruit is a one-seeded drupe, which goes from green to yellow to reddish-brown as it ripens. This brings us to the seed. Date seeds are oblong, ventrally-grooved and have a small embryo. A hard endosperm made of cellulose surrounds the embryo, which is surrounded by the mesocarp (the fleshy, sweet part of the date) and finally the epicarp or exocarp (the date’s skin). These are common features of the seeds of many fruits, and my search to uncover just what allowed Methuselah’s seed to remain viable for two millennia revealed little.

Seed longevity is poorly understood by the scientific community, but is gaining more attention with the growing interest in (and need for) seed banks. A 2008 paper by Loïc Rajjou and Isabelle Debeaujon, Seed longevity: Survival and maintenance of high germination ability of dry seeds, sums up our current understanding of the different factors that affect seed longevity. Rajjou and Debeaujon report that seeds are able to protect themselves with their testa (seed coat), antioxidants, and by reducing their metabolic activity; seeds also have the ability to repair their DNA and decontaminate themselves. It is not clear which of the above qualities allowed the Phoenix dactylifera seeds found in Israel to remain viable for such an extraordinary long time, but it is likely that high levels of antioxidants present in date seeds contributed to this high longevity (date seeds are being studied for antioxidant qualities which could be used to improve human health and longevity). The date seeds also benefited from the dry, dark conditions present in Masada Fortress.

Science overload? Have a look at Shevaun Doherty’s artistic exploration of the Methuselah date for an entirely different way of understanding Phoenix dactylifera.

Phoenix dactylifera

15 responses to “Phoenix dactylifera”

  1. James Singer

    Aah, my favorite palm. One of the interesting things about P. dactylifera is that it is promiscuous; it will readily cross with many other Phoenix species (maybe all of them), with the result of some very spectacular landscape trees.

  2. Bonnie

    Wow, very cool!

  3. Joe

    This looks like a nice palm, but why would I care much about something that is in zone 11??
    Could you please feature more plants that are actually in our zone?
    Thank you.

  4. Marilyn Brown

    Thanks for the link to Shevaun Doherty’s watercolors. Such “extras” are one of the many, many delights of BPoD.

  5. michael aman

    @ Joe: most readers of BPoD love plant life in general and are amazed at the variety, adaptability, beauty and tenacity of plants, from single-cell organisms to this phoenix. I look forward to each post

  6. Tamara Bonnemaison

    Hi Joe,
    Point taken about featuring species that will grow in our zones. We of course have a natural interest in the plants that we can actually grow. However, BPotD has an international audience, so we are always trying to balance out local information with write-ups that will appeal to our readers in vastly different climates. We’ll keep doing our best to please everyone! Any species in particular you would like to learn about?

  7. Peony Fan

    Fascinating!

  8. Alice

    Please keep featuring plants from all zones. It is fascinating to hear about the great variety throughout the world. This was a particularly fine write-up. Thanks!

  9. 3Point141

    Thank you very much for selecting my image. Thank you also for the accompanying wonderful article.

  10. Wendy

    Please don’t limit yourself in any way! I loved this write-up. The discovery of the ancient seed cache. The excitement of the successful germination. The long wait to discover the sex of the palm. The disappointment in having only half of the necessary complement. The desire for repeat attempts. Such drama! The link to the botanical artist was fascinating. Keep up the great work! And, thanks.

  11. Julie

    I think it’s great to have lots of different types of plants from any old zone. Though I do take note of interesting things that might grow where I live, I love posts like this that include a beautiful photo, good scientific information, and in this case a great story. I can just imagine the excitement when that one single seed sprouted! Keep up the good work.

  12. Robin T. Day

    The fruit clusters you see are born on flattend stalks that may be interpreted as perioles of fertile leaves, not stems, as palms very very rarely produce branches, often only when injured. This is the Fertile Leaf Theory I published 2011 and it would link the fertile leaf of palms with those of Seed Ferns. Discussion welcome.

  13. Lin F

    The Date palm from Israel does grow in our area . There is 3 of them in Rockledge 1 Female that bears dates. the fruit is small because you have to pruin the fruit to make them large. these 3 trees were propergated by seeds brought back from Israel. Two of the trees are very large. Lin

  14. shevaun

    Thank you so much for the mention! Although date trees don’t grow well in northern climates, almost everyone has eaten the fruit or has them in their kitchen cupboard. People are surprised to see how beautiful and how colourful the fresh fruit is, quite unlike the dried brown fruit. I’m hoping to produce a set of paintings for the RHS exhibition, hence my botanical studies. Thanks again.

  15. Robin Day

    Oops, should have been PETIOLES of fertile leaves. Nearly all the fruiting structures of palms look like shortened modified leaves, even coco which developes enormous fruit later on.

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