Effects of temperature and leaf water stress on panicle and flower development of litchi ( Litchi chinensis Sonn.)
1991; Taylor & Francis; Volume: 66; Issue: 3 Linguagem: Inglês
10.1080/00221589.1991.11516161
ISSN0022-1589
Autores Tópico(s)Plant Reproductive Biology
ResumoSummaryHigh day/night temperatures (20/15°, 25/20° and 30/25°C vs. 15/10°C) after panicle emergence decreased the proportion of leafless panicles, increased the proportion of leafy panicles and reverted some reproductive buds to vegetative growth in the five litchi cvs Tai So, Bengal, Souey Tung, Kwai May Pink and Wai Chee. The reversion to vegetative characteristics at high temperatures was accompanied by a reduction in the proportion of female flowers. The relative order for the percentage of female flowers across all temperatures was 'Wai Chee' > 'Bengal' > 'Souey Tung' > Tai So' > 'Kwai May Pink'. 'Kwai May Pink' plants exposed to short periods of low temperatures (2, 4 or 8 weeks after panicle emergence at 15/10°C) before transfer to high temperatures (30/25°C) had a lower proportion of female flowers compared with plants maintained continuously at 15/10°C. A cyclical leaf water stress (pre-dawn leaf water potential of —2.0 MPa vs. —0.6 MPa) after panicle emergence reduced panicle length and dry weight and induced flower drop in 'Kwai May Pink' litchi grown at 20/15°C. Water stress also eliminated female flowering (24.8% female flowers in control trees). It was concluded that temperature and water conditions after panicle emergence have strong effects on reproductive development and sex ratio in litchi. Localities which experience warm winters (daily maximum temperatures above 25°C) are best avoided for litchi culture. Litchi trees should be irrigated at full rates from panicle emergence to prevent moisture stress reducing fruit set.
Referência(s)