Comparison of Leaf and Fine Root Traits Between Annuals and Perennials, Implicating the Mechanism of Species Changes in Desertified Grasslands

Abstract

Annual species show traits, such as shortleaf lifetimes, higher specific leaf area, and leaf nutrient concentrations, that provided a more rapid resource acquisition compared to perennials. However, the comparison of root traits between the annuals and perennials is extremely limited, as well as the trade-offs of leaf and fine root traits, and resource allocation between leaf and root, which may provide insight into the mechanism of species changes in arid and semi-arid areas. With lab analysis and field observation, 12 traits of leaf and fine root of 54 dominant species from Horqin Sandy Land, Northeastern China were measured. The organization of leaf and fine root traits, and coordination between leaf and fine root traits of annual and perennial plants were examined. Results showed that there were differences between annuals and perennials in several leaves and fine root traits important in resource acquisition and conservation. Annuals had higher leaf area (LA), specific LA (SLA), and specific root length (SRL) but lower leaf dry-matter content (LDMC), leaf tissue density (LTD), leaf carbon concentration (LC), and fine root dry-matter content (FRDMC) than perennials. Leaf nitrogen (LN) concentration and fine root nitrogen concentration (FRN) were negatively related to LTD and FRDMC in annuals, while FRN was positively related to FRTD and fine root carbon concentration (FRC), and LA was positively related to LN in perennials. These implied that annuals exhibited tough tissue and low palatability, but perennials tend to have smaller leaves to reduce metabolism when N is insufficient. Annuals showed significant positive correlations between FRC/FRDMC and LDMC/LTD/LC, suggesting a proportional allocation of photosynthate between leaf and fine root. In perennials, significant negative correlations were detected between LN, LC, and SRL, fine root tissue density (FRTD), as well as between LA and FRTD/FRC. These indicated that perennials tend to allocate more photosynthate to construct a deeper and rigid roots system to improve resource absorption capacity in resource-limited habitats. Our findings suggested that annuals and perennials differed considerably in terms of adaptation, resource acquisition, and allocation strategies, which might be partly responsible for species changes in desertified grasslands. More broadly, this work might be conducive to understand the mechanism of species changes and could also provide support to the management and restoration of desertified grassland in arid and semi-arid areas.

Coordinated variation in root and leaf functional traits of Hippophae rhamnoides treated at different stump heights in feldspathic sandstone areas of Inner Mongolia

“…Plants subjected to nutrient restriction or interspecific competition will increase the specific root length and root specific surface area to improve the acquisition capacity or competitiveness of nutrients ( Kraft and Ackerly, 2010 ; Yang et al., 2014a ). A decrease in tissue density or dry matter content in roots or leaves can rapidly accelerate plant growth turnover, so the loss of moisture and nutrients will decreased, thus improving the efficiency of use of moisture and nutrient and improving the defense force ( Laughlin et al., 2021 ; Ning et al., 2022 ).…”

“…Together with WinRHIZO Pro 2012b (Regent Instruments Inc., Quebec City, Canada), leaf areas, leaf volumes, total fine root length, and fine root volumes were measured. Subsequently, the leaves and roots in each sample were placed in water and stored away from light at 4°C for 24 h ( Ning et al., 2022 ). After the water was saturated, the surface water of the leaves or fine roots was sucked using absorbent paper, and then the saturated fresh weight of the leaves or fine roots was measured.…”

“…matter content in roots or leaves can rapidly accelerate plant growth turnover, so the loss of moisture and nutrients will decreased, thus improving the efficiency of use of moisture and nutrient and improving the defense force (Laughlin et al, 2021;Ning et al, 2022).…”

“…Apparently, there is a tradeoff and synergy among the functional traits of the leaves. Unlike the leaf trait syndrome, the traits of fine roots belong to be a more complex multidimensional economic space that reflects the diverse evolution pressures and tradeoffs in the underground part ( Kong et al., 2014 ; Xia et al., 2021 ; Ning et al., 2022 ). The large specific root length, small diameter and low tissue density of fine roots are related to the high respiration rate and high turnover rate, and such trade-off is similar to the economic spectrum of leaves ( Caplan et al., 2019 ; Laughlin et al., 2021 ).…”

Identification and Characterization of Arthrobacter nicotinovorans JI39, a Novel Plant Growth-Promoting Rhizobacteria Strain From Panax ginseng

“…An independent sample t -test was used to test the expression of defense enzyme genes and soil enzyme activity. The statistical analyses were carried out by SPSS 26.0 (Sun et al, 2019 ; Ning et al, 2022 ).…”