Annual Herbaceous Plants Exhibit Altered Morphological Traits in Response to Altered Precipitation and Drought Patterns in Semiarid Sandy Grassland, Northern China

Abstract

The frequency and intensity of extreme precipitation events and severe drought are predicted to increase in semiarid areas due to global climate change. Plant morphological traits can reflect plant responses to a changing environment, such as altered precipitation or drought patterns. In this study, we examined the response of morphological traits of root, stem, leaf and reproduction meristems of annual herbaceous species to altered precipitation and drought patterns in a semiarid sandy grassland. The study involved a control treatment (100% of background precipitation) and the following six altered precipitation treatments: (1) P(+): precipitation increased by 30%, (2) P(++): precipitation increased by 60%, (3) P(-): precipitation decreased by 30%, (4) P(--): precipitation decreased by 60%, (5) drought 1 (D1): 46-day drought from May 1st to June 15th, and (6) drought 2 (D2): 46-day drought from July 1st to August 15th. P(++) significantly increased root length, flower length-to-width ratio, both P(+) and P(++) significantly increased stem length and flower number in the plant growing seasons, while all of them decreased under P(-) and P(--). The annual herbaceous plants marginally increased the number of second-level stem branches and stem diameter in order to better resist the severe drought stress under P(--). P(+) and P(++) increased the root, stem, leaf, and flower dry weight, with the flower dry weight accounting for a larger proportion than the other aboveground parts. Under D2, the plants used the limited water resources more efficiently by increasing the root-to-shoot ratio compared with P(-), P(--) and D1, which reflects biomass allocation to belowground increased. The linear mixed-effects models and redundancy analysis showed that the root-to-shoot ratio and the dry weight of various plant components were significantly affected by morphological traits and altered precipitation magnitude. Our results showed that the herbaceous species have evolved morphological trait responses that allow them to adapt to climate change. Such differences in morphological traits may ultimately affect the growing patterns of annual herbaceous species, enhancing their drought-tolerant capacity in semiarid sandy grassland during the ongoing climate change.

Precipitation regime changes alter allometry and plasticity of meristem allocation in annual herbaceous plants in a semiarid sandy grassland, northern China

“…A precipitation experiment with a complete randomized block design was established in April of 2011. It had one control, an ambient environment (Amb; 100% of background precipitation [P]), and six treatments: (1) P(+), precipitation increased by 30%; (2) P(++), precipitation increased by 60%; (3) P(−), precipitation decreased by 30%; (4) P(− −), precipitation decreased by 60%; (5) drought 1 (D1), 46‐day drought in the seedling stage from May 1st to June 15th; and (6) drought 2 (D2), 46‐day drought in the reproductive stage from July 1st to August 15th (Figure S1b; Sun et al, 2022). The soil properties (pH, electrical conductivity in 0–10 cm depth, bulk density in 10–20 cm depth, coarse sand, fine sand, very fine sand, and silt and clay) remained constant with precipitation treatments except for the soil water content (Table S1).…”

“…O. Kuntzae; Corispermum macrocarpum Bge. ; and Tribulus terrestris L.) (Sun et al, 2022). The long‐term mean annual precipitation (MAP) is approximately 360 mm and mean annual temperature is approximately 6.4°C.…”

“…There were 48 2 × 2 m plots, 6 per treatment, and 12 in the control group (Figure S1c). We used clear corrugated polycarbonate slats that intercepted 30% (P[−]) and 60% (P[− −]) of the rainout shelter throughout the year, which we sprinkled in the corresponding P(+) and P(++) plots immediately after the rain (Sun et al, 2022). We also covered the plots with flashing board in May 1st for D1 and in July 1st for D2 and unveiled the board on June 15th for D1 and on August 15th for D2 (Sun et al, 2022).…”

“…O. Kuntzae; Corispermum macrocarpum Bge. ; and Tribulus terrestris L.) (Sun et al, 2022). The long-term mean annual precipitation (MAP) is approximately 360 mm and mean annual temperature is approximately 6.4 C. Soil taxonomy is classified as chestnut type based on the Chinese classification and as Haplic Calcisol based on the Food and Agriculture Organization (Su et al, 2006).…”

“…(3) P(À), precipitation decreased by 30%; (4) P(À À), precipitation decreased by 60%; (5) drought 1 (D1), 46-day drought in the seedling stage from May 1st to June 15th; and (6) drought 2 (D2), 46-day drought in the reproductive stage from July 1st to August 15th (Figure S1b; Sun et al, 2022). The soil properties (pH, electrical conductivity in 0-10 cm depth, bulk density in 10-20 cm depth, coarse sand, fine sand, very fine sand, and silt and clay) remained constant with precipitation treatments except for the soil water content (Table S1).…”