Spatial pattern of variation in populations of Acacia nilotica in semi-arid environment

Abstract

Variability among populations was analyzed in five provenances of Acacia nilotica from spatially variable habitats. Populations of A. nilotica developed in response to their habitat conditions. The level of variability was significantly high among the populations. Phenotypic variability was extremely high for leaf and stipular spine characteristics. The nature of morphological variability for vegetative traits appeared environmentally controlled. The differentiation of leaf and stipular spine expression seems to have an adaptive significance for the species in terms of water economy. Although, seed and pod characteristics are genetically controlled showing a lower proportion of variability but these traits supported r and k-selection that may allow the species to survive under a wide array of contrasting habitats. The study suggested that populations of A. nilotica are differentiated in relation to the heterogeneity of environment. These populations became adapted to their habitat through the variability of morphological expressions. The morphologically differentiated populations of the species had allowed them to maintain themselves in a wide array of environmental situations enabling A. nilotica to occupy ample ecological ranges.

A taxonomic analysis of the Sudanese medicinal plant, Vachellia nilotica L. (syn: Acacia nilotica L.) based on pods, seeds, and vegetative traits

“…It has been recognized worldwide as a multipurpose leguminous tree species (Kaur et al, 2005;Solomon-Wisdom & Shittu, 2010;Elzaki & Gang, 2019). The species has a wide range of natural distribution in tropical and subtropical areas from Egypt and Mauritania southwards to southern Africa and Asia eastward to the Indian subcontinent (Caesariantika et al, 2011;Solomon-Wisdom and Shittu 2010;Mahmood et al, 2005). Moreover, it is valuable mainly for timber and fuel wood production (Elzaki & Gang, 2019), tannin production (Haroun et al, 2009;Elkhalifa et al, 2005 andBanso, 2009).…”

“…The diversity of sites and climatic conditions under which this species grows led to the evolution of an extremely variable species a puzzled taxonomic history and nomenclature. Thus, its taxonomy worldwide is recognized by nine subspecies; among these, the subspecies indica, cupressiformis, and hemispherica are native to India and Pakistan, subspecies hemispherica is endemic to Pakistan (Mahmood et al, 2005) and the subspecies nilotica, tomentosa, leiocarpa, subalata, kraussiana, and adstringens are from Africa (Chhillar et al, 2002).…”

“…Branchlet pilosity is either glabrous, glabrescent, puberulous, pubescent, or tomentose and mature pod characteristics in the term of shape, margin shape, and degree of the pubescence are either "necklace-like, narrowly and regularly constricted between seeds with different degrees of pubescence and colour", as in the subspecies tomentosa, nilotica, indica, and cupressiformis, or "not necklace-like with straight or crenate margins and different degree of pubescence and colour" as in the subspecies leiocarpa, subalata, kraussiana, adstringens, and hemispherica (Chhillar et al, 2002;Mahmood et al, 2005). In Africa, wooded grassland, dry scrub forests, and savanna are the ecological preferences for subspecies subalata, leiocarpa, and adstringens, while riverine habitats and seasonally flooded areas are preferable for subspecies nilotica and tomentosa.…”

Germinación y crecimiento inicial de Acacia senegal (Linne), Acacia seyal (Del.) y Boswellia papyrifera

“…Las semillas de A. senegal son más grandes que las de A. seyal, y los valores del número de semillas por kg son inferiores a los indicados en estudios anteriores . Estas diferencias pueden ser debidas al origen del material utilizado, ya que estas especies habitan en diferentes altitudes y condiciones climáticas y que estas condiciones ambientales influyan en la morfología de las semillas (Miller et al, 2002;Mahmood et al, 2005) estudio en las semillas de la especie Acacia nilótica en Pakistán, Loha…”

“…and Tigabu (2008) en las semillas de la especie Cordia africana). Según Mahmood (2005) se demostró la existencia de diferencias en la morfología de las semillas entre poblaciones de la misma especie y que en el caso nuestro la diferencia en cuanto a la cantidad de las semillas/kg en especies Acacias respecto al estudio realizado por , puede ser debido a esto, ya que las semillas utilizadas en este experimento fueron mas grandes que las utilizadas en el previo estudio realizado, donde las procedencias de las semillas en los dos casos es diferente, con una diferencia de altitud de 100 msnm. En las semillas de la especie Boswellia papyrifera la morfología es muy distinta a las de Acacia, con semillas pequeñas y abundantes (90,000/kg).…”