Hernandez Jonathan O, An Ji Young, Combalicer Marilyn S, Chun Jong-Pil, Oh Sang-Keun, Park Byung Bae
Department of Environment and Forest Resources, Chungnam National University, Daejeon, South Korea.
Department of Forest Biological Sciences, College of Forestry and Natural Resources, University of the Philippines Los Baños, Los Baños, Philippines.
Front Plant Sci. 2021 Dec 7;12:738301. doi: 10.3389/fpls.2021.738301. eCollection 2021.
A better understanding of plant drought responses is essential to improve plant water use efficiency, productivity, and resilience to ever-changing climatic conditions. Here, we investigated the growth, morpho-anatomical, physiological, and biochemical responses of Carruth., Murray, and Regel to progressive water-stress. Seedlings were subjected to well-watered (WW) and water-stressed (WS) conditions while regularly monitoring the soil volumetric water content, stem diameter (SD), height, biomass, stomatal conductance (g), intercellular CO concentration (C), and leaf relative water content (RWC). We also investigated the variation in stomatal pore (SP) area, specific leaf area (SLA), root xylem vessel diameter (VD), and total soluble sugar (TSS) concentration between treatments. After 2 months, WS significantly suppressed SD growth of and but had no impact on . Total biomass significantly declined at WS-treated seedlings in all species. WS resulted in a smaller SLA than WW in all species. The SP of WS-treated seedlings of and significantly decreased, whereas it increased significantly with time in . Larger vessels (i.e., >100 to ≤ 130) were more frequent at WS for and , whereas smaller vessels (i.e., >40 to ≤ 90) were more frequent at WS than at WW for after 8 weeks. Tylosis was more frequent at WS than WW for and at eighth week. WS seedlings showed lower g, C, and RWC compared with WW-treated ones in and . TSS concentration was also higher at WS-treated seedlings in two species. Overall, principal component analysis (PCA) showed that SLA and SP are associated with WS seedlings of and and the tylosis frequency, TSS, and VD are associated with WS seedlings of . Therefore, water-stressed plants from all species responded positively to water stress with increasing experimental duration and stress intensity, and that is largely explained by morpho-anatomical traits and soluble sugar concentration. The present study should enhance our understanding of drought-induced tree growth and short-term tree-seedling responses to drought.
更好地理解植物对干旱的响应对于提高植物水分利用效率、生产力以及应对不断变化的气候条件的恢复力至关重要。在此，我们研究了Carruth.、Murray和Regel对渐进性水分胁迫的生长、形态解剖、生理和生化响应。将幼苗置于充分浇水（WW）和水分胁迫（WS）条件下，同时定期监测土壤体积含水量、茎直径（SD）、高度、生物量、气孔导度（g）、细胞间CO浓度（C）和叶片相对含水量（RWC）。我们还研究了处理间气孔孔（SP）面积、比叶面积（SLA）、根木质部导管直径（VD）和总可溶性糖（TSS）浓度的变化。2个月后，WS显著抑制了Carruth.和Murray的SD生长，但对Regel没有影响。所有物种中，WS处理的幼苗总生物量显著下降。所有物种中，WS导致的SLA均小于WW。Carruth.和Murray的WS处理幼苗的SP显著降低，而Regel的SP随时间显著增加。8周后，Carruth.和Murray在WS条件下较大的导管（即>100至≤130）更常见，而Regel在WS条件下较小的导管（即>40至≤90）比WW更常见。第八周时，Carruth.和Murray在WS条件下的侵填体比WW更常见。在Carruth.和Murray中，WS处理的幼苗与WW处理的相比，g、C和RWC较低。两个Carruth.物种中，WS处理的幼苗TSS浓度也较高。总体而言，主成分分析（PCA）表明，SLA和SP与Carruth.和Murray的WS幼苗相关，侵填体频率、TSS和VD与Regel的WS幼苗相关。因此，所有物种的水分胁迫植物随着实验持续时间和胁迫强度的增加对水分胁迫产生了积极响应，这在很大程度上由形态解剖特征和可溶性糖浓度来解释。本研究应能增强我们对干旱诱导树木生长以及树木幼苗对干旱的短期响应的理解。
