Comparative Analysis of Growth and Photosynthetic Characteristics of (Populus simonii × P. nigra) × (P. nigra × P. simonii) Hybrid Clones of Different Ploidides

Abstract

To evaluate differences among poplar clones of various ploidies, 12 hybrid poplar clones (P. simonii × P. nigra) × (P. nigra × P. simonii) with different ploidies were used to study phenotypic variation in growth traits and photosynthetic characteristics. Analysis of variance showed remarkable differences for each of the investigated traits among these clones (P < 0.01). Coefficients of phenotypic variation (PCV) ranged from 2.38% to 56.71%, and repeatability ranged from 0.656 to 0.987. The Pn (photosynthetic rate) photosynthetic photon flux density (PPFD) curves of the 12 clones were S-shaped, but the Pn-ambient CO2 (Ca) curves were shaped like an inverted “V”. The stomatal conductance (Gs)-PPFD and transpiration rate (Tr)-PPFD curves had an upward tendency; however, with increasing PFFD, the intercellular CO2 concentration (Ci)-PPFD curves had a downward tendency in all of the clones. The Pn-PPFD and Pn-Ca curves followed the pattern of a quadratic equation. The average light saturation point and light compensation point of the triploid clones were the highest and lowest, respectively, among the three types of clones. For Pn-Ca curves, diploid clones had a higher average CO2 saturation point and average CO2 compensation point compared with triploid and tetraploid clones. Correlation analyses indicated that all investigated traits were strongly correlated with each other. In future studies, molecular methods should be used to analyze poplar clones of different ploidies to improve our understanding of the growth and development mechanisms of polyploidy.

Variation Analysis of Physiological Traits in Betula platyphylla Overexpressing TaLEA-ThbZIP Gene under Salt Stress

“…In this research, the CSP of the four different lines ranged from 596.77 to 701.74 μmol·mol −1 . Below the CSP, the Pn of the four lines ranged from 11.23 to 14.52 μmol m −2 s −1 , similar to the Pn values reported for poplar seedlings [28]. These results indicated that all four lines were able to utilize high concentrations of CO 2 .…”

“…One hundred uniform plants of each line (WT, L-4, L-5, and L-8) were selected as the experimental materials. All plants were watered with a 4 g L −1 NaCl solution every 2 d, and the Pn-photosynthetic photon flux density (PPFD) curves and Pn-CO 2 concentration in air (Ca) curves were measured and analysesed by the method of Zhao [28] on 8 d of the salt treatments. Light saturation point (LSP), light compensation point (LCP), CO 2 saturation point (CSP) and CO 2 compensation point (CCP) were evaluated by fitting the data to the model function as follows: where Y is the Pn value, X is the PPFD (or Ca), b 0 is a constant, and b 1 and b 2 are coefficients.…”

Taxonomic and ecological relevance of the chlorophyll a fluorescence signature of tree species in mixed European forests

“…Another remote sensing parameter, the photochemical reflectance index (PRI), is a proxy for F V / F M (Weng et al ., ). The latter does not correlate necessarily with the actual photosynthetic rates, but, in optimal environmental conditions, high values of F V / F M are related to high photosynthetic capacity (Zhao et al ., ). The assessment of the dark fluorescence on trees, therefore, may be considered as a tool to estimate the potential photosynthetic performance and growth capacity of individual species and forest ecosystems.…”

Protective Effect of Nitric Oxide (NO) against Oxidative Damage in Larix gmelinii Seedlings under Ultraviolet-B Irradiation

“…NO promotes the assembly and stabilization of thylakoid membrane protein complexes and enhances light energy absorption and the utilization ability of the chloroplast. Amax and AQY reflect the state of the photosynthetic apparatus [42]. This investigation showed that under UV-B radiation, Amax, AQY, and other photosynthetic parameters of Larix gmelinii seedlings decreased significantly.…”