Response of Leaf Anatomical Structure and Photosynthetic Characteristics of Winter Turnip Rape ( Brassica rapa L.) to Low Temperature before Winter

• Published in: Zuo wu xue bao Vol. 43; no. 3; p. 432
• Main Authors: XU, Yao-Zhao, ZENG, Xiu-Cun, ZHANG, Fen-Qin, SUN, Jia, SUN, Wan-Cang, WU, Jun-Yan, FANG, Yan, LIU, Zi-Gang, SUN, Bo-Lin
• Format: Journal Article
• Language: English; Chinese
• Published: 2017
• ISSN: 0496-3490
• DOI: 10.3724/SP.J.1006.2017.00432

Stomatal traits,leaf anatomic structure characteristic and diurnal variation of photosynthesis and fluorescence parameters,in two winter turnip rape(B.rapa L.) cultivars Longyou 7(strong cold-tolerant) and Tianyou 4(weak cold-tolerant) were determined under 0[degrees]C and -7.6[degrees]C natural low temperature conditions to clearify the effects of low temperature on leaf anatomical structure,mechanism of photosynthesis and cold resistance.With decreasing the temperature before winter,stomatal density,stomatal area,and total stomatal circumference per unit area in two cultivars decreased.Moreover,leaf thickness,palisade tissue and sponge tissue thickness became thinner and cellular space grew bigger.The diurnal variation of net photosynthetic rate of two cultivars presented a single-peak curve,and no typical mid-day depression occurred.Under the lower temperature,Pn declined with a non-stomatal limitation in two cultivars.Photo inhibition in the two cultivars occurred under low temperature and increased with the temperature decreased.Compared with Longyou 7,Tianyou 4 had bigger stomatal density,stomatal area,total stomatal circumference per unit area and leaf thickness,as well as higher photosynthetic capacity and weaker photo inhibition.In conclusion,higher photosynthesis and faster growth in winter turnip rape under lower temperature may result from its bigger stomatal density,stomatal area and total stomatal circumference per unit area as well as thicker leaf,palisade tissue and sponge tissue,which results in a poorer resistance to cold stress.The result may be useful for mining new germplasm and facilitating winter turnip rape breeding for cold resistance.