田间全日照对蔓越橘光合特性的影响

Effects of full sunlight on photosynthetic characteristics in cranberry seedlings

蔓越橘主要生长于东北林下弱光环境,推广过程中主要在全日照条件下栽培。2种环境相比,光照发生巨大改变,但全日照是否及如何影响蔓越橘生长及光合作用尚不清楚。以蔓越橘优良品系贝恩为试验材料,研究林下和全日照条件下光照强度对其叶片生长和光合特性的影响。结果表明:相比于林下弱光条件,全日照条件显著降低了蔓越橘叶片的叶绿素含量和新叶的叶面积;荧光诱导动力学数据表明,全日照导致蔓越橘PSⅡ天线转化效率降低,而且新叶K和J点相对荧光产量升高,暗示PSⅡ光化学活性和电子传递受阻;通过荧光猝灭分析,观察到全日照下生长的蔓越橘天线转化效率下调,过剩激发能主要通过NPQ耗散;此外,相对于林下弱光,全日照强光还在一定程度上降低了蔓越橘新叶的PSⅠ光吸收,即PSⅠ的活性。综上,虽然在全日照强光下蔓越橘能够对其光合机构进行调节,但强光仍会对其叶片造成一定程度的伤害,尤其对新生叶片。

Cranberry is a shrub under the forest in Northeast China. It is mainly cultivated under the condition of full sunlight in the process of popularization. Therefore, cranberry Barn was used to study the effects of light intensity on leaf growth and photosynthetic characteristics under under-forest and full sunlight conditions. The results showed that the full sunlight significantly reduced the chlorophyll content of cranberry leaves and the leaf area of new leaves compared with the low-light conditions under the forest;fluorescence induction kinetic data showed that the efficiency of cranberry PSⅡantenna was reduced by full sunlight and the relative fluorescence yield of the new leaves K and J points increased, suggesting that PS II photochemical activity and electron transport are blocked;Through the analysis of fluorescence quenching, it was observed that the efficiency of cranberry antennas grown under full sunlight was reduced, and the excess excitation energy was mainly dissipated by NPQ;In addition, the full sunlight light also reduces the PSⅠ light absorption of the new cranberry leaf. Therefore, we believe that although cranberries can regulate their photosynthetic apparatus under full sunlight, full sunlight will still cause some damage to their leaves, especially for new leaves.