PJB-2020-250
Comparison of water adaptability between Coix lacryma-jobi and Coix aquatica based on photosynthesis
Jin-Lan Shi, Zheng-Fu Xu, An-Na He, Can Hu and Zhang-Qiang Lu
Abstract
Coix lacryma-jobi is a traditional Chinese medicinal herbs, and it has a long history of eating and planting in China. This paper compares the photosynthetic physiology and morphological characteristics of C. lacryma-jobi and C. aquatica, according to their characteristics of the environment and natural distribution. In order to explain the photosynthetic physiology and morphological mechanism in adapting to the living environment, and make suggestions for planting of C. lacryma-jobi. The experiment designed four groups of treatment: C. lacryma-jobi planted in dry land (CL-D), C. lacryma-jobi planted in flooded land (CL-F), C. aquatica planted in dry land (CA-D), C. aquatica planted in flooded land (CA-F). Li-6400 portable photosynthesis device was used to measure photosynthesis, TTC method was used to measure root viability, and paraffin section method was used to observe root microstructure. The results showed that, the daily variation of net photosynthetic rate (PN) of CA-D treatment group was slightly lower than that of other groups. PN of CA-D was significantly lower than that of CA-F in August. The light response curve also showed that the PN of CA-D was lower than other groups. Stomatal limitation was the main factor affecting PN and E. Chlorophyll fluorescence parameter results showed that there was no obvious adversity in the four groups of treatments. However, the photochemical quenching (qP) and apparent electron transfer rate (ETR) of the two species under dry cultivation were significantly lower than those of flooded cultivation. The adverse effect of dry cultivation on the electron transport capacity of C. aquatica was greater, and the chlorophyll content of C. aquatica in dry land was also significantly lower than in flooded land. Root vigor of the two plants under flooded culture was higher than that of dry land in August. The root cross-section structure of the two species was very similar. Parenchymatous parenchyma cells increased and formed ventilated tissue in flooded land. The vascular bundles number of C. lacryma-jobi was significantly more than that of C. aquatica under dry land. Adequate water could increase leaf area, tiller number, and fruiting rate of the two species. In summary, both types of the plants are more suitable for a well-watered environment, so sufficient water must ensure when planting C. lacryma-jobi. And the adaptability of C. lacryma-jobi to dry land is stronger than that of C. aquatica, which indicates that the C. aquatica has slowed down during the evolution process.
To Cite this article:
Shi, J.L., Z.F. Xu, A.N. He, C. Hu and Z.Q. Lu. 2022. Comparison of water adaptability between Coix lacryma-jobi and Coix aquatica based on photosynthesis. Pak. J. Bot., 54(1): DOI: http://dx.doi.org/10.30848/PJB2022-1(36)
Download
