Growth and Physiology of Senegalia senegal (L.) Britton Seedlings as Influenced by Seed Origin and Salinity and Fertility Treatments

Abstract

Abstract:Multipurpose trees such as Senegalia senegal are widespread in arid and semi-arid lands that have natural or induced saline soils and poor soil fertility. Such environmental problems impact growth and have the potential to influence plant physiological adaptations. Identifying superior genotypes better adapted to these environmental stresses will be of great importance for tree selection for reclamation of degraded drylands. The main objective of this study was to examine the growth performance, and physiological and morphological adaptations to salinity, and fertility treatments of different Senegalia senegal families. We used five families (DB16, DB14, K4B19, K17B19, NB1) selected from 60 families of a Senegalia senegal progeny trial in Dahra, Senegal. Seedlings were grown under greenhouse conditions by watering all plants for three weeks and then stopping all watering for three more weeks. In a randomized complete block design, a two-level factorial combination was used for salinity (zero and 183.1 mM NaCl added) and fertility (zero and 100 kg/ha N-P-K added) treatments. A significant family × salt × fertilizer interaction was found for all biomass parameters (leaf dry matter, stem dry matter, root dry matter, and leaf area). The fertilizer application resulted in a significant increase of total biomass of all families, ranging from 63% to 237% for NB1 and K17B19, respectively. In contrast, salt only decreased total biomass of NB1 and K17B19 increased growth. Despite similar net photosynthetic rates before treatment started, fertilizer and salinity induced different effects between families. Prior to drought stress, fertilizer did not affect photosynthesis of DB16, while salt significantly decreased stomatal conductance of all families. DB16 and N1B1, despite significant differences of stomata size and density, significantly decreased transpiration, and thereby increased their intrinsic water use efficiency. Under drought, relative growth rate was significantly decreased. Given that genotype differences were found, these families and salinity and fertilizer treatments need to be explored in field trials.

Effect of Drought Stress on the Physiology and Early Growth of Seven Senegalia senegal (L.) Britton Provenances

“…It appears likely for these seed sources that under drought stress stomatal conductance regulates water loss through transpiration thereby affecting net photosynthetic rate (Farquhar 1982). The greater drop of leaf gas exchanges between control and drought treatments noticed on Ngane at the second dry down cycle may be explained by its speci c stomatal size and density compared to other Senegalia senegal provenances (Sarr et al 2017, Bertolino et al 2019). However, few study exists on the link between stomatal morphology and tree response to drought.…”

Drought resistance and gum yield performances in a Senegalia senegal (L.) Britton progeny trial in Senegal

“…− 28.50‰ (Gray et al 2013). This may explain the greater growth rate and attributes in Ngane (Sarr et al 2017).…”

Photochemical efficiency and growth of two provenances of Acacia senegal )gum arabic( tree seedlings under drying soil

“…Xeric plants possess mechanisms enable them to avoid detrimental effects of drought and maintain productivity under limited water resources (Rambal and Leterme, 1987). Therefore, identifying superior genotypes better adapted to stressful environments would be of great interest in tree selection for dryland afforestation (Sarr et al, 2017). Acacia senagal variations in height, basal diameter and number of branches have been given primary importance in tree selection for restoration and agroforestry in Sudan (Raddad, 2007).…”