Foliar characteristics, cambial activity and wood formation in Azadirachta indica A. Juss. as affected by coal–smoke pollution

Behavioral responses of leaves and vascular cambium ofProsopis cineraria(L.) Druce to different regimes of coal-smoke pollution

“…Leaf NRA did not show any obvious correlation with leaf area and/or lamina mass per unit area in Camptotheca accuminata seedlings (Sun and Yan 2004). Whereas NR activity in P. cineraria declined with increasing degrees of pollution, the reverse was true for nitrate contents (Figure 3), thus conforming to the situation observed recently in Peristrophe bicalyculata (Nighat et al 2008) and Azadirachta indica (Iqbal et al 2010). NR activity was at its lowest during winter, when nitrate content was usually high.…”

“…In general, xylem production took longer than phloem production, a situation reported recently for A. indica also (Iqbal et al 2010). Rajput et al (2008) have reported a onemonth delayed initiation and one-month early cessation of cambial activity in Prosopis spicigera facing pollutants released by a fertilizer complex, compared with the normal cambial periodicity in a clean environment.…”

“…In consequence of a reduced photosynthesis, concentration of reducing sugars in leaves of P. cineraria declined with growing pollution load, showing a minimum at the most-polluted site ( Figure 4), as was the case with P. bicalyculata (Nighat et al 2008) and A. indica (Iqbal et al 2010). The relatively high sugar content during the pre-monsoon or monsoon periods could possibly emanate from a breakdown of starch into simple sugars during these periods of active growth.…”

“…The rate of cambial cell division and the length of the active phase of cambium determine the extent of the annual production of secondary vascular tissues (Iqbal 1995). Atmospheric pollutants may influence the phenomena of development (Wali et al 2007) and seasonal activity (Rajput and Rao 2005) of the cambium as well as the formation of secondary vascular tissues (Iqbal et al 2010).…”

Effects of soil pollution on seedling growth characteristics of Tamarindus indica L.

“…The addition of suspended particulate matters (SPM) may affect soil pH, electrical conductivity (EC) and the nutrition status of the soil (Iqbal, et al, 2000). The pollutants produced due to combustion, including SO2 and NO2, may harm forests as well as crop fields causing tree decline and/or reduced yields (Iqbal, et al, 2010). The ever increase of petroleum derived products such as gasoline, diesel and motor oil, has led to a marked increase in soil contamination and produced toxic effects on plant growth (Anon, 2003;Shahid, 2007;Njoku, et al, 2009;Houshmandfar and Asli, 2011;Iqbal et al, 2016).…”