Smoke-water is a chemical extract used to stimulate the germination of many plant species under cultivation. This study evaluated the efficacy of smoke-water on the seed germination and seedling growth of papaya (Carica papaya cv. Tainung No. 2). Smoke-water, prepared from dry rice straw (Oryza sativa) by burning and bubbling the smoke through water, was used for germination experiments, growth experiments, and anatomical structure changes of seeds. In the germination experiments, papaya seeds were soaked with different concentrations of smoke-water (0.1%, 0.2%, 1%, 2%, 3%, 4%, 5%, 7%, or 10%, v/v) for 24 h before planting. Low concentrations of smoke-water (0.1% or 0.2%, v/v) not only promoted the maximum rate of germination, but also shortened the germination time. Analysis of longitudinal sections of seeds treated with smoke-water concentrations of 0.1% or 0.2% v/v suggested that smoke-water could overcome water impermeability barriers, because it stimulated the seedcoat to rupture and allowed the radical to elongate and emerge faster. In the growth experiments, papaya seedlings were transplanted into peatmoss-filled pots that were saturated with different concentrations of smoke-water (0%, 1%, 2%, 3%, 4%, 5%, 7%, or 10%, v/v). Results showed that all growth parameters increased significantly compared with the control. In addition, smoke-water treatments consistently and significantly increased the percentage of nitrogen in roots and shoots and significantly increased the percentage of magnesium in shoots. In these experiments, smoke-water showed potent germination promotion at low concentrations and promoted multiple growth attributes such as chlorophyll content and seedling vigor index at all concentrations in papaya seedling production.
Jenjira Chumpookam, Huey-Ling Lin and Ching-Chang Shiesh
San-Gwang Hwang, Yi-Ying Li and Huey-Ling Lin
The king oyster mushroom [Pleurotus eryngii (DC.:Fr.) Quél.] is gaining popularity across the world due to its excellent taste, high nutritional quality, medicinal value, and long shelf life. Conventional substrates for king oyster mushroom cultivation consist of sawdust derived from various tree species. Sawdust demand is increasing worldwide, creating a need for alternative materials that can at least partially replace sawdust as substrate for king oyster mushroom. In Taiwan, as in other countries that grow fruit trees, pruned fruit tree branches are an expensive agricultural waste, particularly if they are not recycled or reused. In the present study, we evaluated substrates containing sawdust and different proportions of material ground from pruned wax apple or Indian jujube branches for cultivation of king oyster mushroom. Our results suggested that among all five substrate mixes tested, the best substitute for conventional sawdust (100% sawdust) was a substrate that contained 75% sawdust mixed with 25% materials ground from trimmed wax apple branches (Wax apple 25%). Furthermore, determination of mineral element content, pH, and electrical conductivity (EC) levels of the substrates both before spawn inoculation and after harvesting revealed no significant changes in mineral content, a slight reduction in pH value, and a minor increase in EC levels after cultivation. Taken together, results from this study suggest that agricultural wastes from pruned fruit tree branches can partially replace sawdust as the cultivation substrate for king oyster mushroom.
San-Gwang Hwang, Hsiao-Chien Chao and Huey-Ling Lin
Global surface temperatures are predicted to increase by 1 to 4 °C by the year 2100. To unravel the risks from rising temperature to Taiwan’s summer leafy vegetable production, the phenotypical and physiological responses of two leafy crops, pak choi (Brassica chinensis L. cv. Quanzhou) and edible amaranth (Amaranthus tricolor L. cv. White leaf), were compared under an elevated temperature. A temperature increase from 28 to 32 °C resulted in lower leaf calcium, magnesium, and manganese concentrations (dry weight basis) in pak choi without significant changes in shoot dry weight, suggesting potential negative effects of the elevated temperature on pak choi leaf nutrient status. However, increased temperature promoted both root and leaf growth in edible amaranth, which may be beneficial to its yield, making edible amaranth a potential summer leafy vegetable crop for Taiwan. Furthermore, a temperature change from 28 to 32 °C resulted in a higher leaf nitrate concentration in edible amaranth, because of the lower nitrate reductase activity (NRA). Thus, suitable nitrogen fertilization rates and programs under elevated temperature conditions should be reconsidered in the future. To sum up, a future rise in summer temperatures may impose negative impacts on pak choi leaf nutrient status but positive impacts on edible amaranth production.
Huey-Ling Lin, Jenjira Chumpookam, Ching-Chang Shiesh and Wen-Hsin Chung
The antifungal efficacy of smoke-water on damping-off caused by Pythium sp. was evaluated both in vitro and in vivo. Smoke-water was generated by burning plant material and bubbling the smoke through water; its effect on the morphology of Pythium sp. was investigated by scanning electron microscope (SEM). Mycelia growth and oospore production of the fungus were significantly inhibited when cultured on water agar amended with smoke-water at 0%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, or 5%. In growth chamber experiments with potted seedlings growing in peatmoss, papaya plants treated with smoke-water exhibited reduced symptoms of damping-off when compared with control plants treated with water. Furthermore, the pots treated with 1.5% or higher smoke-water did not show any symptoms of damping-off disease. Plant height significantly increased with treatment by higher concentrations of smoke-water. Maximum plant height was observed with treatment of 1% smoke-water or higher concentrations. One day after smoke-water application, SEM observations of the Pythium sp. revealed loss of structural integrity, abnormal degradation, deformation, abnormal lysis, cytoplasmic leakage, and hyphal slimming. This study showed that the addition of smoke-water to soil exerted significant disease suppression against Pythium sp., leading to improved growth of papaya seedlings.
Choun-Sea Lin, Huey-Ling Lin, Wann-Neng Jane, Han-Wen Hsiao, Chung-Chih Lin, Fang-Yi Jheng and Wei-Chin Chang
A xylem mutant (vse) was isolated from a Bambusa edulis (Odashima) Keng plantlet following vegetative micropropagation and subculture for 7 consecutive years and induced to proliferate in medium supplemented with 0.1 mg·L-1 (0.5 μm) thidiazuron (TDZ) and to develop roots in medium supplemented with 5 mg·L-1 (26.9 μm) α-naphthaleneacetic acid (NAA). Subsequent investigations comparing the growth habits of mutant plantlets with those of the wild type indicated that the growth of the former was retarded in a greenhouse. Several morphological abnormalities were observed in the vse mutant: it had thinner stems with fewer trichromes on the surface; the xylem vessels were smaller in diameter and contained crystal-like structures in the pith; the leaves were shorter and narrower with a sharp leaf blade angle; the roots were thinner and contained fewer xylem cells. The cation concentrations of both the mutant and wild type were similar in the in vitro analysis, except for those of iron and potassium, which were lower in mutant leaves in vivo. In 2-month-old mutant plants, iron chlorosis was observed on young leaves and a potassium deficiency was observed on older leaves. After 1 year of growth in the greenhouse, all of the wild-type plants had survived, but only 27% (16/60) of the mutant vse plants were alive.