BACKGROUND AND AIMS: The shoot apical meristem (SAM) is the key organizing element in the plant body and is responsible for the core of plant body organization and shape. Surprisingly, there are almost no comparative data that would show links between parameters of the SAM and whole-plant traits as drivers of the plant's response to the environment. METHODS: Interspecific differences in SAM anatomy were examined in 104 perennial herbaceous angiosperms. KEY RESULTS: There were differences in SAM parameters among individual species, their phylogenetic patterns, and how their variation is linked to variation in plant above-ground organs and hence species' environmental niches. SAM parameters were correlated with the size-related traits of leaf area, seed mass and stem diameter. Of the two key SAM parameters (cell size and number), variation in all organ traits was linked more strongly to cell number, with cell size being important only for seed mass. Some of these correlations were due to shared phylogenetic history (e.g. SAM diameter versus stem diameter), whereas others were due to parallel evolution (e.g. SAM cell size and seed mass). CONCLUSION: These findings show that SAM parameters provide a functional link among sizes and numbers of plant organs, constituting species' environmental responses.

• Keywords
• Corner’s rule, cell number, cell size, genome size, phylogenetic analysis,
• MeSH
• Phylogeny MeSH
• Magnoliopsida anatomy & histology   growth & development   MeSH
• Meristem anatomy & histology   growth & development   MeSH
• Organogenesis, Plant MeSH
• Plant Shoots anatomy & histology   growth & development   MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH

A rapid warming in Himalayas is predicted to increase plant upper distributional limits, vegetation cover and abundance of species adapted to warmer climate. We explored these predictions in NW Himalayas, by revisiting uppermost plant populations after ten years (2003-2013), detailed monitoring of vegetation changes in permanent plots (2009-2012), and age analysis of plants growing from 5500 to 6150 m. Plant traits and microclimate variables were recorded to explain observed vegetation changes. The elevation limits of several species shifted up to 6150 m, about 150 vertical meters above the limit of continuous plant distribution. The plant age analysis corroborated the hypothesis of warming-driven uphill migration. However, the impact of warming interacts with increasing precipitation and physical disturbance. The extreme summer snowfall event in 2010 is likely responsible for substantial decrease in plant cover in both alpine and subnival vegetation and compositional shift towards species preferring wetter habitats. Simultaneous increase in summer temperature and precipitation caused rapid snow melt and, coupled with frequent night frosts, generated multiple freeze-thaw cycles detrimental to subnival plants. Our results suggest that plant species responses to ongoing climate change will not be unidirectional upward range shifts but rather multi-dimensional, species-specific and spatially variable.

• MeSH
• Biodiversity MeSH
• Climate Change * MeSH
• Population Dynamics * MeSH
• Plants classification   MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Geographicals
• India MeSH