In contrast, foliar application of caffeine decreased the C.

gloeosporioides actin gene was gradually increased during the post-inoculation period. Here we show that elevated CO2 reduced endogenous caffeine content in tea leaves, but sharply increased susceptibility of tea to C. However, its effect on Colletotrichum gloeosporioides that causes brown blight disease in tea is largely unknown especially under elevated CO2. Interactions between factors regulatingĬaffeine, the major purine alkaloid in tea has long been known for its role in plant defense. Inhibition of A as a result of photoinhibition was minimized, but not eliminated, by abundant N. End‐product inhibition of A is not consistent with decreased Ci. Analysis of the responses of A to environment in the morning compared to the afternoon, and of chlorophyll fluorescence, suggests that A was photoinhibited as a consequence of greatly increased PAR, whilst decreasing gs (related to changes in PAR, VPD and TL) caused Ci to fall. Leaves of unshaded plants receiving least N had significantly (P<0.05) smaller A and greater total sugar content than shaded but with abundant N, A and sugars did not differ between shade treatments. The zero‐N treatment decreased total‐N content of leaves by 50% and A by c. In the late afternoon, irradiance, TL and VPD fell, but despite the relatively large increase in gs and Ci, A remained low however, it recovered overnight. However, as the irradiance, TL and VPD increased towards midday, A, gs, photochemical quenching, and Ci decreased, and non‐photochemical quenching increased. Stomatal conductances (gs) and substomatal carbon dioxide concentrations (Ci) were then large, leaf temperatures (TL) cool, and saturated water vapour deficits (VPD) small.

When recently fully expanded leaves were measured under the growing conditions on bright, clear days from dawn to dusk,Ī was greatest in the morning with increasing radiation between approximately 8 h and 10 h. These treatments were combined with nitrogen fertilizer applications of 0, 360 and 720 kg ha−1 year−1. Were either unshaded, receiving 100% of incident photosynthetically active radiation (PAR), moderately shaded, (65% PAR) or Kuntze) bushes grown at high elevation in the field in Sri Lanka, were related to environmental conditions. This documentation is mainly targeted at tea planting community, policy makers and other users such as researchers, national and international research institutes and multilateral organizations dealing with sustainable tea cultivation, development and livelihood security of dependents.ĭiurnal changes in the rate of photosynthesis (A) of mature tea (Camellia sinensis (L.) O. It is a joint effort by the scientists of Tea Research Institute of India, Sri Lanka, Kenya and China supported by the FAO-IGG on tea in Rome. This compilation of adaptation strategies for tea cultivation developed and practiced by major tea growing countries of the world, is the first step taken by the working group on climate change of the FAO-IGG on tea to minimize climate change impacts on tea plantations. Increasing temperatures, changes to rainfall amount and distribution, coupled with major shifts in other meteorological parameters in comparison with long term observations have further complicated the production process. Presently, the climate change triggered by global warming is posing a major threat to the resilience of agricultural systems including tea cultivation. Tea is the most used beverage second to water in the world.

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