Response of Cryptocoryne pallidinervia Engler (Araceae) on light intensity and water depth

The study of the effect of different light intensities and water depths on the growth pattern, biomass allocation and photosynthetic rate of Cryptocoryne pallidinervia collected from Sungai Prasak, Keranji, Lundu, Sarawak, Malaysia, was conducted. Plants grown under tree canopy condition produced more leaves and lateral shoots than those grown under 50 % and 75 % shading. By increasing shade to 75 % level, the plants grew taller with larger leaves. The expansion of individual leaves at 75 % shade required 51 days to reach maximum size. The growth pattern such as leaf weight ratio (LWR), petiole weight ratio (PWR), rhizome weight ratio (RhWR) as well as root weight ratio (RWR) and biomass allocation such as specific leaf area (SLA), leaf area ratio (LAR), dry matter production (DMP), leaf area duration (LAD) and net assimilation rate (NAR) were significantly affected by shading. Plants grown in the depth of 15 cm were significantly taller and required a longer period to achieve maximum leaf expansion than those grown at 0 cm and 7 cm water depth. Growth pattern and biomass allocation were also significantly affected by water depths. Plants grown under 75 % shading and those grown at 0 cm water depth resulted in higher maximum quantum yield. However, plants at 75 % shade and those at 7 cm water depth had higher photosynthetic production at 300 μmol quanta m^-2s^-1 than those from other shade regimes and water depths.