JIP-test in assessing sensitivity to nitrogen deficiency in two cultivars of Actinidia arguta (Siebold et Zucc.) Planch. ex Miq

Optimal nitrogen availability is necessary to keep high photosynthetic efficiency and in consequence, good physiological condition and growth of plants. In order to examine the effect of N nutrition on photosynthetic apparatus performance we used the chlorophyll a fluorescence (ChF) technique in two differing Actinidia cultivars and we aimed to select the most reliable ChF parameters showing N deficiency. The 4-years-old specimens growing on an experimental plantation were treated with three differing N doses and ChF data were collected during two years. The results showed that PSII performance indices, performance index on the absorption basis and total performance index, are useful to detect the overall decrease in photosynthetic apparatus vitality. Efficiency of electron movement beyond Q(A) into the electron transport chain was more susceptible to different N nutritions than maximum quantum efficiency, while a pool of Q(A) reducing reaction centres per PSII antenna chlorophyll, RC/ABS, and a number of Q(A) reducing reaction centres per cross section of a sample, RC/CS0, were the best indicators of N deficiency.