Effects of soil water conditions on seedling regeneration in Myricaria laxiflora remnant populations

Abstract

Remnant populations of Myricaria laxiflora are degrading due to difficulties in regeneration. To uncover the critical factors that hinder the regeneration of M. laxiflora populations, the present study examined seed persistence, seed germination and seedling survival and growth under different soil water contents and groundwater levels. Results revealed that seed viability significantly decreased with prolonged storage time. The germination rate of seeds stored for 15 days was 10.9%, which was 79.8% lower than unstored seeds. The viability of seeds was also significantly influenced by soil water content. The germination rate under the 0 g g −1 soil water content treatment was 105.3% higher than 0.10 g g −1 soil water content. Groundwater level significantly affected seed germination and seedling growth. The suitable groundwater level for seed germination and seedling growth was between −10 and −15 cm, at which, the germination rate, seedling survival rate and seedling biomass reached their highest values. Compared to the 0 and −20 cm groundwater levels, the −10 cm level resulted in a 16.8% and 166.7% higher germination rate, 14.1% and 9.2% higher seedling survival rate and 116.7% and 82.0% higher aboveground biomass, respectively. The longest main roots were observed at the −15 cm groundwater level. Therefore, it was concluded that changes in soil water content and groundwater level affect the regeneration of remnant M. laxiflora populations. K E Y W O R D Sgroundwater level, Myricaria laxiflora, seed germination, seed viability, seedling survival and growth

Branches and Leaves Growth Patterns in Myricaria laxiflora Remnant Populations Are Affected by Human-altered Water Level Fluctuations

“…An investigation on the M. laxi ora remnant populations by Bao et al (2010) revealed that the remnant population structure had an extremely low ratio of young seedlings, indicating a population degradation caused by the hindered population regeneration. In our recent study on the growth and reproduction characteristics of M. laxi ora remnant populations, sexual reproduction, photosynthetic activity and seedling establishment were signi cantly reduced due to the changes in the water level uctuation pattern (Chen et al, 2019;Guan et al, 2020a;Guan et al, 2020b). This study further elucidated the effects of regulated water-level uctuations on the formation and changes in M. laxi ora branch and leaf growth traits.…”

“…Because M. laxi ora have extremely small leaves, their young branches (green-colored) are also important photosynthetic organs. A decrease in the number of branch and leaves will affect the photosynthetic capability and the accumulation of organic matters of plants (Guan et al, 2020b), which further in uences the plant growth and sexual reproduction after ood (Chen et al, 2019: Guan et al, 2020a. This could explain why M. laxi ora populations continue to degenerate under the regulated water level uctuation pattern (Bao et al, 2010).…”

“…Capsules are narrowly conical and measure 6-8 mm in length. Seeds measure 1-1.5 mm in length and are dispersed by the wind and river water ow (Chen and Xie, 2007;Guan et al, 2020a). M. laxi ora is mainly distributed in the riparian zone between Yichang at the Yangtze River and Yibin in the Jinsha River.…”

Temporal and spatial responses of the branch and leaf growth relationship to human water flow regulation: a case study on remnant Myricaria laxiflora populations

“…The groundwater level during the dry season of winter has also been reduced significantly (Duan et al 2016). Human water flow regulation severely impacted seedling regeneration, photosynthetic physiology and sexual reproductive efficiency of the remnant M. laxiflora populations (Bao et al 2010;Chen et al 2019D:\Praveen\TF-TJFE200012\7;Guan et al 2020aGuan et al , 2020b .…”

The global biogeography and environmental drivers of fairy circles

“…Fairy circles (FCs) are regularly spaced patches of bare ground surrounded by tall grasses ( 1 – 3 ). So far, FCs have only been found in drylands of Namibia and Australia ( 4 ), where harsh conditions hamper plant regeneration ( 5 ). However, there are pronounced differences between Australian and Namibian FCs.…”