| Micropropagated strawberry (Fragaria ananassa Duschsne. cv. Fengxiang) was used to study their growth and physiological responses to sucrose concertration added in the MS medium,PPFD and CO2 concertration during rooting in vitro and the persistent effects during acclimatization ex vitro in the experiments.The results are as follows:1. Effects of micro-environment factors in vitro on the growth and photosynthesis of strawberry plantlets during rooting stage: Nodal cuttings were cultured on solid Murashige-Skoog medium with 3% sucrose or without sucrose, and in low (60 10umol . m-2 . s-1) or high (150 10 mol . m-2 . s-1) photosynthetic photon flux densities, and normal (350 50 L L-1) or elevated (700 100 L L-1) CO2 concentration for 20 days. The results indicated that 3% sucrose was beneficial to biomass formation of plantlets, higher PPFD and elevated CO2 concentration were both of benefit to the growth of plantlets. But higher PPFD reduced the chlorophyll content, and a slight negative effect on photosynthesis could be found in the culture conditions of 3% surose without elevated CO2. And elevated CO2 was helpful for the development of photosynthetic capacity,especially under the higher PPFD.2. Effects of micro-environment factors in vitro on the development of strawberry plantlets during acclimatization ex vitro: After 20 days of rooting culture (the treatments were same as 1) , plantlets were transplanted to the greenhouse for a month period of acclimatization.At the first days, the distinctive effects of the different in vitro culture conditions on growth were maintained,and along with the acclimatization,the difference in growth among the treatments were decreased. At day 15 afer transplant,the differences in chlorophyll content and the ratio of chlorophyll to carotenoids content disappeared.And after transplant there was an slight decline in net photosynthesis rate at the plantlets cultured on medium without sucrose,then ascended. Compared to in vitro plantlets,transplanted plants had higherPn and PSII and qp,as indicated that the photosynthetic capability developed further. The response of the antioxidant enzymes indicated that protective mechanisms were activated.3. Effects of the photomixotrophic degree during rooting in vitro on the subsequent growth and physiological characteristics ex vitro: Nodal cuttings were cultured on solid MS medium and rooted under two different conditions: 1)3% sucrose, PPFD SOumol m"2 s"1, ambient CO2 concentration 350-400 uL L"1; 2) 0.5% sucrose, PPFD 90umol m'2 s"1, ambient CO2 concentration 700-800 uL L"'.For 20 days culture,the plantlets were transplanted to greenhouse for acclimatization under two irradiations(shaded or not).Before transplant, the plantlets grown under condition 1 had higher value in height,fresh weight ,leaf area and SLA,whereas the dry matter percent and LWR were lower. At the end of rooting culture,the chlorophyll content of plantlets grown under condition 1 was higher and the soluble carbohydrates and sucrose and starch content were lower.After transplant,the differences among treatments were mostly attributed to the two irradiations in glasshouse.The results about water status showed that the plantlets rooted under condition 2 had higher RWC,lower stomatal aperture and transpiration.lt indicated their water-keep ability were better than the plantlets grown under condition 1.During the acclimatization,the RWC declined firstly, then ascended.The activities of SOD and CAT of plantlets rooted under condition 2 were both higher. And after acclimatization,the plants under unshaded environment had preferable growth,especially the plants rooted under condition 2.1t was likely the plantlets grown under condition 2 had developed better photosynthetic apparatus.As could be concluded from the Pn and chlorophyll fluorescence parameters(Fv/Fm, Fv/Fo, PS , ETR, qP, qN...
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