Foliar summer frost resistance measured via electrolyte leakage approach as related to plant distribution, community composition and plant traits

Abstract

Frost resistance (FR) is a fundamental process determining various aspects of plant life. Measurements of FR remain challenging as existing methods are time‐ and labour‐intensive. Here, we test the applicability of foliar summer FR measured via the ‘electrolyte leakage’ approach (FRPEL), a simple and inexpensive technique so far underused in ecological research to estimate FR. We tested the ability of this trait to predict (a) species occurrence, (b) community composition along an elevation gradient and (c) analysed its relationship with nine other traits (SLA, Cmass, Nmass, Pmass, Camass, Mgmass, Kmass, canopy height and the ability to form rosettes) related to plant performance. We studied 183 vascular species occurring at 37 sites, which we also analysed in terms of species composition along an elevation gradient from 656 to 2,363 m a.s.l. in the Bavarian Alps, Germany. Species' FRPEL values correlated significantly with the species occurrence along the elevation gradient. However, this relationship was weak as it explained only 10% in the variation of the Landolt indicator values, a proxy for species geographic ranges. We found a strong positive relationship between community‐weighted FRPEL values and elevation suggesting a strong environmental filtering of this trait that removes species with low FR from the local species pool at high elevations. The community functional diversity of FRPEL significantly increased with increasing elevation suggesting a higher trait divergence in harsher climates. We found significant negative relationships between FRPEL and SLA, canopy height and the ability to form leaf rosettes, indicating a trade‐off in plants between the investment in conservative strategies, in our case FR, and fast resource acquisition. Our study highlights the potential of using FRPEL more frequently in ecological research as we were able to reconfirm three patterns inferred by more precise yet time‐consuming and labour‐intensive approaches. We demonstrate that FRPEL can be used to predict species occurrence and infer assembly rules along elevation gradients. Furthermore, we found that FRPEL is linked to plant functional traits associated with plant performance and morphological features of the plants. However, the trait's predictive power varied greatly among the study objectives and levels. A free Plain Language Summary can be found within the Supporting Information of this article.

Is the Seasonal Variation in Frost Resistance and Plant Performance in Four Oak Species Affected by Changing Temperatures?

“…However, during the year plants need to balance between the maintenance of photosynthesis and the investment in FR as both are quite energy demanding. In this vein, a trade-off between these two traits is expected and has been reported previously [1,5,7].…”

“…As already described by [42], F v /F m was a good indicator of autumn senescence in deciduous species. The decrease of F v /F m over the winter in evergreen species may be connected to the increase in FR and would confirm the hypothesized trade-off between FR and photosynthetic performance, as shown by [1,5,7]. PI abs showed similar responses as F v /F m .…”

“…As Q. ilex originates from the central-western Mediterranean basin [53], it might be possible that this species did not express a strong trade-off between FR and photosynthetic parameters overall because there is no need for this investment in its climate of origin. A higher photosynthetic performance for the other species might be possible considering the species in the greenhouse did not need to invest, as seen above, into FR which was also found by [1,5,7]. Also, Adams et al [41] suggest that when temperatures are significantly below freezing no photosynthesis is possible.…”

“…FR can be captured via measuring the effective percentage of electrolyte leakage (Effective PEL, PEL eff ), which is an easy, cheap, and robust method for measuring high Forests 2021, 12, 369 2 of 15 numbers of plant individuals [7,8]. Capturing the photosynthetic performance can be achieved through various methods, such as determining chlorophyll a fluorescence via the JIP-Test [9][10][11][12][13].…”

Inferring community assembly processes from functional seed trait variation along elevation gradient

“…Likely because of the weak trade‐off between those traits and frost resistance, species from the lowlands invest less in protecting their leaves against negative temperatures (high CWMs for frost sensitivity in lowlands; Figure 2). The convergent FD values in those grasslands further suggest that frost‐resistant plants are excluded from these communities, likely due to their comparatively low competitiveness (Bucher & Rosbakh, 2021). In contrast, the high FD for canopy height indicates that both small and tall plants can co‐occur, suggesting that some degree of niche partitioning associated with this trait maintains species coexistence in those competitive environments (Münkemüller et al, 2020).…”