Photosynthetic Characteristics of \u3ci\u3eVeratrum californicum\u3c/i\u3e in Varied Greenhouse Environments

Corn lily or California false hellebore (Veratrum californicum Durand), a perennial species native to the western United States, produces several alkaloid compounds. A derivative of these alkaloid compounds, primarily veratramine and cyclopamine, shows promise as a therapeutic agent for treatment of a variety of tumor types. Here we report the first study of corn lily cultivated in greenhouse. Growth response of corn lily was examined under two light levels (ambient and supplemental), two fertilization types (20 N-4.4 P-16.6 K Peat-lite special and 15N-2.2P-12.5K CalMag special) at 100-mg·L-1 total nitrogen, and three irrigation cycles [sub-irrigation every day (wet), every third day (dry), and hand watering]. Net CO2 assimilation rate (Pn) and transpiration rate (ET) of corn lily grown under supplemental light were 11.0% and 44.7%, respectively, higher than those under ambient light. The Pn and ET of corn lily grown with the wet irrigation cycle increased by 15.2% and 29.4%, respectively, when compared with the Pn and ET of plants grown under the dry irrigation cycle. Corn lily grown wet with supplemental light had the highest average Pn of 8.55 ± 0.36 μmol·m-2·s -1, while plants grown under ambient light with hand watering had the lower average Pn of 6.52 ± 0.48 μmol·m-2·s -1. The highest mean ET recorded for corn lily was 4.97 ± 0.17 mmol·m-2·s -1 when plants were grown dry with supplemental light, while the lowest ET recorded was 2.51 ± 0.18 mmol m-2 s-1 when plants were grown under ambient light and hand with supplemental light and when volumetric water content remained above 44%. The water use efficiency of corn lily may be low, as water is not normally limiting in the natural environment where corn lily grows

Chilling Requirements to BreakDormancy of \u3ci\u3eVeratrum californicum\u3c/i\u3e

Veratrum californicum, a native of the western United States, has long been used in herbal medicine and now also has potential pharmaceutical uses. As a result of a projected increasing demand for V. californicum biomass for pharmaceutical purposes, the development of a chilling protocol for enhanced cultivation efficiency is needed. To study the effects of chilling on the growth of V. californicum, field-collected rhizomes with attached bulbs and roots were potted, stored at 10 °C for 2 weeks, and subsequently chilled at 5 °C for 30 to 180 days before transfer to a greenhouse or growth room. Twenty plants were transferred to the greenhouse every 30 days to observe growth. Ten plants were harvested at shoot emergence and the remaining 10 when leaves were fully expanded. In addition, 10 plants were transferred from 5 °C to a growth room every 30 days where net photosynthetic rates were measured. Longer chilling duration correlated with a reduction in days to shoot emergence and leaf expansion. The net photosynthetic rates of V. californicum plants chilled for 120, 150, or 180 days were higher than those of plants chilled for only 30, 60, or 90 days. Plants exposed to longer chilling durations were taller and had larger, more numerous leaves. Interestingly, V. californicum shoot emergence was also observed in the dark at 5 °C after the bulbs had been stored for 210 days. Growth of the root systems of plants was also observed during chilling. In conclusion, chilling was necessary at 5 °C for a minimum of 120 days to force early emergence and vigorous growth of V. californicum