Pollen morphological variability correlates with a large-scale gradient of aridity
Pollen morphological variability correlates with a large-scale gradient of aridity
复制标题
花粉形态变异与大范围的干旱梯度相关
DOI：
10.5194/we-20-19-2020
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发表时间：
2020
期刊：
影响因子：
2.2
通讯作者：
Haroun Chenchouni
中科院分区：
文献类型：
--
作者：
H. Fatmi;S. Maalem;Bouchra Harsa;A. Dekak;Haroun Chenchouni
摘要。对生物体形态的研究对于理解是必不可少的
Abstract. The study of the morphology of living organisms is essential to understand
their evolution and diversity. This study aims to determine the importance
of climatic gradients in the diversity of pollen morphotypes using Atriplex halimus L.
(Amaranthaceae) as a model species. Atriplex halimus is a perennial shrubby plant,
polymorphic and very resistant to severe environmental conditions. In seven
bioclimatic zones, ranging from mesic conditions in the north to
hot–hyperarid in the south, pollen samples were collected from 49 sites,
with seven accessions per bioclimate. Under a light microscope, pollen grains
were selected and analyzed from three anthers of different flowers. Besides
the usual pollen grain types, some previously unknown morphotypes, such as
sulcate, triangular, and ovoid, were observed and described at the different
climatic zones. A total of 10 pollen grain shapes were quantified and
discussed following their specific occurrences within different climatic
zones. Occurrence frequencies of different pollen shapes ranged between 0 %
and 85.7 %, where the pantoporate spheroidal was the most widespread in
all climatic zones, especially in the desert climate (85.7 %). Five
pollen types occurred exclusively once per climate zone. The pantoporate
prolate spheroidal in mesomediterranean climate with a long dry season
(28.6 %), sulcate in the xerothermomediterranean climate (14.3%),
pantoporate subtriangular in the subdesert climate with a short dry season
(14.3 %), and pantoporate subprolate and boat-shaped in a subdesert
climate with a long dry season with 14.3 % for each. Our findings help to
understand the evolutionary effects of climate gradients on pollen
morphology and variability in arid and desert areas and point towards a
high degree of specialization in order to maximize trade-offs between
pollination efficiency and protection of pollen grains from dehydration.