PHOTOSYNTHETIC CHARACTERISTICS OF YOUNG ‘ZAOZHONG NO.6’ LOQUAT TREES GRAFTED ON DIFFERENT ROOTSTOCKS

The photosynthetic characteristics of young Eriobotrya japonica Lindl. ‘Zaozhong No.6’ loquat trees grafted on five different rootstocks: Fragrant loquat (E. fragrans Champ.), Guangxi loquat (E. kwangsiensis Chun.), Bengal loquat (E. bengalensis Hook.), E. japonica ‘Jiefangzhong’ and wild tree E. japonica) were analyzed with Li-6400 portable photosynthesis system under field conditions.
Diurnal changes in net photosynthesis rate (Pn) in loquat leaves of spring shoots in summer presented two peaks.
The first peak occurred at 11:00am when Pn of ‘Zaozhong No.6’ loquat grafted on Fragrant loquat seedling was
13.95 µmol m^-2 s^-1, the highest among all graft combinations.
The second peak occurred at 3:00pm and was lower than the first one.
In autumn, diurnal variations of Pn in leaves of spring shoots of ‘Zaozhong No.6’ grafted on Fragrant loquat and ‘Jiefangzhong’ showed a single-peak pattern, while the other graft combinations had two peaks.
The peak Pn of ‘Zaozhong No.6’ loquat grafted on Fragrant loquat was 8.68 µmol m^-2 s^-1. In ‘Zaozhong No.6’ loquat grafted on Fragrant loquat, the daily variation of stomatal conductance (Gs) in leaves of spring shoots presented two peaks in summer.
Diurnal changes in Gs in leaves of spring shoots of ‘Zaozhong No.6’ loquat grafted on Fragrant loquat presented bimodal curve in autumn.
The diurnal curve of transpiration rate (Tr) in leaves of spring shoots of ‘Zaozhong No.6’ loquat grafted on Fragrant loquat and Guangxi loquat had two peaks in autumn.
The diurnal change patterns of photosynthetic parameters were affected by rootstock.
There were complex relationships between Pn and Gs and between Tr and intercellular CO₂ concentration (Ci).

II International Symposium on Loquat

H.L. Zhang, S.Q. Lin, Y.L. Hu, J.G. Li, X.H. Yang, X.L. He

Eriobotrya japonica, physiology

https://doi.org/10.17660/ActaHortic.2007.750.61