Influence of soil moisture regimes on growth, photosynthetic capacity, leaf biochemistry and reproductive capabilities of the invasive agronomic weed; Lactuca serriola

Abstract

Global temperatures are predicted to increase by 1.5–5.9°C during this century, and this change is likely to impact average rainfall, with predictions that water deficit will perhaps be the most severe threat to sustainable agriculture. In this respect, invasive weeds, which have traits better adapted to drought stress than crops, add to concerns regarding crop sustainability. Lactuca serriola , an aggressive agronomic weed is thought to be a successful weed because of its ability to maintain high water use efficiency under drought conditions. In this study, experiments were conducted to examine the influence of different soil moisture regimes (100%, 75%, 50% and 25% water holding capacity (WHC)) on growth, photosynthetic capacity, leaf biochemistry and reproduction of this species. Soil moisture significantly affected plant’s height, stem diameter, number of leaves and biomass. The highest plant height (115.14 cm ± 11.64), shoot diameter (9.4 mm ± 0.18), leaf area (1206.5 mm 2 ± 73.29), plant fresh weight (83.1 ± 3.98) and dry weight (22.38 ± 1.24) were recorded at 75% soil moisture content. A fundamental adaptation to drought was observed as plants in the 25% WHC treatment had the highest root: shoot ratio. Soluble sugars and total phenolic content were highest in the 25% WHC treatment and significantly different to 100% WHC which was a response to soil moisture stress to ameliorate the damaging effects of reactive oxygen species produced under stress conditions. Results also indicate that L . serriola can survive and produce seeds under water stress as more than 6000 seeds were produced per plant in all WHC treatments. In this study, there was no significant difference in the seed weight, number of seeds produced and their germination ability. This can have a huge impact on agricultural systems as the species can survive both under low and high soil moisture conditions. We therefore suggest that the demonstrated ability of L . serriola to complete its life cycle and produce biomass and seeds under water stressed conditions leads to the introduction of strategies that minimize weed survival while maximizing irrigation efficiency for the crop. A clear understanding of the ecological and biological characteristics of this weed will help land managers take appropriate control measures to mitigate the effect of this species on economic crop productivity.

Influence of soil moisture levels on the growth and reproductive behaviour of Avena fatua and Avena ludoviciana

“…Similarly, another study observed 52 leaves plant -1 for Lactuca serriola L. at 100% WHC as compared with 42 leaves plant -1 at 50% WHC. At 100% WHC, A. fatua and A. ludoviciana plants took 38 and 30 days for 50% tillering (Table 1; Figs 2b and 3b) [38]. For A. fatua and A. ludoviciana, the number of leaves per plant followed a similar sigmoidal trend at 60, 80 and 100% WHC (Figs 2c and 3c).…”

“…fatua and A . ludoviciana plants took 38 and 30 days for 50% tillering ( Table 1 ; Figs 2b and 3b ) [ 38 ]. For A .…”

Effect of drought stress on herbicide performance and photosynthetic activity of Avena sterilis subsp. ludoviciana (winter wild oat) and Hordeum spontaneum (wild barley)

“…did not reduce under drought-stress conditions (water holding capacity (WHC) 75%) in comparison with well-watered conditions (WHC 100%) (Chadha et al, 2019). The lack of detrimental effect of the drought conditions on stomatal conductance and photosynthesis rate of H. spontaneum might be due to its ability to tolerate different abiotic stresses because H. spontaneum is an abiotic-stresses tolerant weed species (Wang et al, 2018).…”

Effect of Cropping and Management Techniques on Chilli (Capsicum annuum L.) Production under Rain-Fed Farming

“…Similar result is supported by Govaerts et al (2007) that the soil moisture variability is associated with designing raised bed methods. According to Chadha (2019) soil moisture significantly attributed to growth parameters. Ghosh et al (2018) further reported that soil moisture involves in nutrient transportation to roots and nutrient solution equilibrium.…”