Effects of different biobased mulch types on photosynthesis, transpiration and stomatal conductance of Quercus nuttallii saplings.

摘要

Photosynthesis helps control the temperament of our atmosphere, understanding photosynthesis is important to understanding how carbon dioxide and other "greenhouse gases" affect the global climate (Gust, 1996). Measurements of photosynthesis are required for comparing and understanding biomass accumulation of vegetal systems at the leaf, plant or community level as well as their response to environmental stresses (Millan et al, 2009). Further, limited information is available on whether organic mulch influences gas exchange (Montague et al., 2007). However, sometimes the results from mulching are variable, being affected by different environmental conditions and by different tree species (Whitcomb, 1980; Iles and Dosmann, 1999).;This study focused on the Quercus nuttallii (Nuttall Oak) under five organic mulches (Pine Bark, Mixed Hardwoods, Pine Needles, Mixed Oaks, and Pine Bark + Pine Wood) and control (No-Mulch) which applied to determine their influence on net photosynthesis, transpiration and stomatal conductance and to quantify their effect of dynamics on Nuttall Oak growth and development in one growing season. Monthly measurements of leaf-level gas exchange were made periodically, using a portable photosynthesis system (LICOR System Inc.). Measurements were taken of similar mature leaves and also weekly physiological-environmental measurements included plant responses such as photosynthesis, stomatal conductance and transpiration.;In this study, we concluded Nuttall Oak net photosynthesis fluctuated statistically significant under different mulch types in one growing season and net photosynthesis mean was higher under pine bark + pine wood mulch type and under mixed hard wood had lower mean value during one growing season. Also, stomatal conductance (gs) mean and transpiration rate was statistically significantly different under PBPW, MH, MO, NM, PB and PN mulch types and control (NM) showed highly significantly difference in one growing season. This study contributes to better understanding of how environmental factors such as soil moisture influence plant responses. The research also identifies important aspects related to the efficiency of urban organic mulch management that need to be studied further.