Leaf Gas Exchange Response of 'Arapaho' Blackberry and Six Red Raspberry Cultivars to Moderate and High Temperatures

Abstract

<jats:p>Leaf gas exchange of six red raspberry (<jats:italic>Rubus idaeus</jats:italic> L.) and one blackberry (<jats:italic>Rubus</jats:italic> L. subgenus <jats:italic>Rubus</jats:italic> Watson) genotypes growing in 12-L containers was measured at four temperatures (20, 25, 30, and 35 °C) once a month for 3 months in growth chambers by infrared gas analysis. Measurements were taken on three successive leaves on the same primocane between the third and seventh nodes (≈75% to 85% of full leaf expansion). The plants were grown in ambient (field) conditions except when measurements were taken. Maximum daily ambient temperatures rose as high as ≈37 °C during this period. Net CO<jats:sub>2</jats:sub> assimilation (A), evapotranspiration (ET), and stomatal conductance (<jats:italic>g<jats:sub>s</jats:sub></jats:italic>) were measured during June, July, and August. Significant differences (<jats:italic>P</jats:italic> ≤ 0.01) in A were found among the seven genotypes. 'Arapaho' blackberry displayed the highest mean A rate at all temperatures. Only in the raspberry cultivars Nova and Reveille did the rate of A drop significantly when temperature increased from 20 to 30 °C. 'Reveille' was also the only cultivar in which A significantly declined between 30 and 35 °C. The ET increased significantly over the four temperatures in four cultivars ('Arapaho', 'Heritage', 'Nova', and 'Southland'). The ET rate at 35 °C was higher for 'Arapaho' than for all other cultivars. 'Autumn Bliss', 'Dormanred', and 'Reveille' did not change significantly as the temperature rose from 20 to 35 °C. Stomatal conductance of 'Heritage' and 'Arapaho' did not change significantly between 20 and 35 °C, whereas that of 'Autumn Bliss' and 'Reveille' declined almost 50% when temperature increased to 30 or 35 °C.</jats:p>

Water relations advantages for invasive Rubus armeniacus over two native ruderal congeners

“…Although R. parviflorus and R. spectabilis do not have low physiological rates-the g s rates we measured were greater than many cultivated Rubus and other Pacific Northwest trees and shrubs in late spring (Waring and Franklin 1979;Stafne et al 2001)-both native Rubus species faced significant water limitation in summer. In effect, our results suggest that R. armeniacus experienced a less extreme summer drought even compared to these vigorous natives.…”

“…By maintaining high stomatal conductance, gas-exchange processes can be minimally curtailed under drought conditions such as those of Pacific Northwest summers (Stephenson 1990). Although stomatal conductance (g s ) is not always limiting to CO 2 assimilation (A) in Rubus species (Stafne et al 2001); McDowell and Turner (2002) found g s and A to be well correlated in both R. armeniacus and the Pacific Northwest native R. ursinus. A strong ability to maintain active gas exchange through both spring and summer conditions may make light more limiting than water to the invasive success of R. fruticosus.…”

Persistent negative temperature response of mesophyll conductance in red raspberry (Rubus idaeus L.) leaves under both high and low vapour pressure deficits: a role for abscisic acid?

“…; Stafne et al . ; Hall & Sobey ). We evaluated g m from 20 to 35 °C, which is representative of the maximal daytime T leaf differential experienced by raspberry leaves out in the open field on sunny summer days in southern Québec where plants were obtained.…”

“…In this study, we evaluated the short-term temperature response of g m in red raspberry (Rubus idaeus L.), an economically important horticultural crop of northern hemisphere origins, which readily adapts to cool temperate climatic conditions (Hall & Sobey 2013). Net photosynthesis in red raspberry is optimal below 25°C, peaking typically around 17-21°C (Percival et al 1996;Stafne et al 2001;Hall & Sobey 2013). We evaluated g m from 20 to 35°C, which is representative of the maximal daytime T leaf differential experienced by raspberry leaves out in the open field on sunny summer days in southern Québec where plants were obtained.…”

Veränderte Temperaturbedingungen als Folge des Klimawandels und ihre Bedeutung für den Erdbeer- und Himbeeranbau

“…Einen negativen Einfluss der steigenden Temperatur (Bereich 10-30°C) auf die Pollenkeimung und damit letztendlich auf den zu erwartenden Fruchtansatz konnten Leech et al (2002) Stafne et al (2001) im Bereich von 20-35°C, mit einer 40%igen Abnahme, wenn die Temperatur von 20 auf 35°C anstieg. Nach Cameron et al (1993) liegt das Temperaturoptimum der Fotosynthese und damit der Kohlenhydratproduktion bei Himbeeren im Bereich von 12-20°C.…”