{"id":5797,"date":"2020-12-15T04:02:00","date_gmt":"2020-12-15T04:02:00","guid":{"rendered":"https:\/\/research.reading.ac.uk\/herbarium\/?p=5797"},"modified":"2020-12-15T09:03:23","modified_gmt":"2020-12-15T09:03:23","slug":"adventbotany-day-15","status":"publish","type":"post","link":"https:\/\/research.reading.ac.uk\/herbarium\/2020\/12\/15\/adventbotany-day-15\/","title":{"rendered":"#AdventBotany Day 15, The date palm revisited; elderly seeds and a primer for sex determination"},"content":{"rendered":"

By Claudia Ciotir<\/a><\/h2>\n

Date palm (Phoenix dactylifera<\/em> L.), is a socio-economically important\u00a0 tree due to its food, fibre and construction material uses in arid and semiarid regions of the world. It is a monocotyledonous dioecious tree producing male and female flowers on separate individual plants. Morphologically, male inflorescences are protected by an inflated spathe with flowers developing visible petals and anthers, while female flowers lacking petals are protected by a flat spathe with globular ovaries (Figure 1).<\/p>\n

\"Bracts
Figure 1. Morphological characteristics of date palm inflorescences and spathes in a male (Left) and female tree (Right) (Intha and Chaiprasart 2018). https:\/\/doi.org\/10.1016\/j.scienta.2018.03.039<\/figcaption><\/figure>\n

Origin of date palms<\/h3>\n

The origin of date palm remains obscure (Mohamoud et al. 2019) and molecular evidence suggests multiple domestication events. Morphometric analysis of seed shape (Gros-Balthazard et al. 2016, 2017; Terral et al. 2012) indicates an origin in the Middle East around the Persian Gulf with some of the most distinct populations in the mountains of Oman.\u00a0 The Persian Gulf region near Abu Dhabi has ancient Neolithic sites with preserved charred seeds calibrated to the late sixth and early fifth millennia BCE (Beech and Shepherd 2001). Recently Zehdi-Azouzi et al. (2015) have sugested multiple origins of domesticated dates due to the very distinctive patterns of genotype found in north Africa in contrast with those typical of the Middle East.<\/p>\n

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Origin of the 295 date palm accessions classified into ten groups and two regions: I and II as defined according to their spatial and genetic proximity. Region I, Mauritania, Algerian, Morocco, Tunisia and Egypt; region II, Djibouti, Oman, the UAE, Iraq and Pakistan. The colours correspond to the genetic clusters defined by STRUCTURE analysis, with cluster I in green and cluster II in red. (Zehdi-Azouzi et al. 2015) https:\/\/doi.org\/10.1093\/aob\/mcv068<\/figcaption><\/figure>\n

Traditionally, date palm was cultivated in the Middle East and North Africa, later introduced to favourable climates in California, Peru and Australia and in many areas with hot and dry climates (Tengberg 2014). Although dates are essential food and an important commercial crop in Middle Eastern countries, they are currently consumed as winter dry fruit in most countries of the world.<\/p>\n

Long lived seeds<\/h3>\n

The longevity of date palm seeds is outstanding. In Israel, the Judean date palm (extinct from cultivation) has been revived from 1900years old seeds recovered from the historical site of Masada in vicinity of the Dead Sea (Sallon et al. 2008). In Haifa city, as in many areas of warm temperate climate, date palms are planted in public streets and gardens.<\/p>\n