Photosynthetic and Chlorophyll Fluorescence Characteristics of Isodon rubescens (Hemsley) H. Hara

Abstract

photosynthetic and chlorophyll fluorescence characteristics of Isodon rubescens (Hemsley) H. Hara Jian Zaiyou ✉ , Zhou Xiuren & tian Jing the ecological and economic cultivation of Isodon rubescens is currently being carried out. the demand of I. rubescens for light intensity should be made clear to estimate whether the environmental conditions of an area are suitable for cultivating I. Rubescens and improve cultivation techniques. the photosynthetic and chlorophyll fluorescence characteristics of I. rubescens were determined with a Li-6400 photosynthesis system and PAM-2500 portable chlorophyll fluorescence apparatus. The results showed that there was no obvious midday depression of photosynthesis in I. rubescens leaves. the light compensation point and light saturation point of I. rubescens leaves were 21.83482 µmol•m −2 •s −1 and 802.262 µmol•m −2 •s −1 , respectively. the co 2 compensation point and co 2 saturation point of I. rubescens leaves were 101.7199 µmol•mol −1 and 1674.514 µmol•mol −1 , respectively. the maximal photochemical efficiency of photosystem II ((Fm-Fo)/Fm) in I. rubescens leaves reached 0.7. The electron transport rate of photosystem ii in I. rubescens leaves reached 20 μmol electrons/(m 2 •s). I. rubescens can tolerate intense light above the light compensation point and utilize low light. I. rubescens leaves have a strong photoprotective capacity. I. rubescens can grow in both sunny and shady places. the most important factor affecting photosynthetic efficiency in I. rubescens leaves is the concentration of co 2 in air. Isodon rubescens (Hemsley) H. Hara is a perennial subshrub belonging to a genus of the Lamiaceae family 1. There are several bioactive chemical components in I. rubescens, such as oridonin and ponicidin. The dry aerial portions of I. rubescens are named rabdosiae rubescentis herba and are used in traditional Chinese medicine for the treatment of sore throats, inflammation and gastrointestinal problems 2,3. The ecological and economic cultivation of I. rubescens is currently being carried out. However, there are different environmental conditions in different places. Wild I. rubescens grows on mountains or hills. There are obvious differences between the environmental conditions of mountains and plains. The demand of I. rubescens for light intensity should be made clear. The photosynthetic and chlorophyll fluorescence characteristics of I. rubescens were studied in this research to define the most suitable environmental conditions for I. rubescens cultivation and improve cultivation techniques. Results Diurnal variation in I. rubescens leaf photosynthesis. The results of the diurnal variation in I. rubescens leaf photosynthesis are shown in Table 1. Based on the collected data, the curve of the diurnal variation in I. rubescens leaf photosynthesis is shown in Fig. 1. The diurnal variation in I. rubescens leaf photosynthesis indicates that there was no obvious midday depression of photosynthesis. There is still a high net photosynthetic rate in I. rubescens leaves at noon w...

Acclimatization of photosynthetic apparatus and antioxidant metabolism to excess soil cadmium in Buddleja spp.

“…For instance, the non-regulated Y(NO) is made up of nonphotochemical quenching due to photoinactivation and constitutive thermal dissipation 35 . Generally, the value of Y(NO) has been found to be positively associated with the extent of photodamage 33,34 In this study, Cd exposure did not significantly (p > 0.05) increase the values of Y(NO) in both studied Buddleja species under any of the Cd treatments. Compared with B. asiatica, B. macrostachya plants exhibited high Y(NO) values (as NPQ and Y(NPQ)) ( Fig.…”

“…Plant species not only can utilize most of the energy in light for photosynthesis, but also can efficiently dissipate the excessive excitation energy into harmless heat 33 , 34 . The extent of heat dissipation is closely related to the NPQ capacity 35 .…”

“…The extent of heat dissipation is closely related to the NPQ capacity 35 . The efficiency of the dissipation of excessive excitation energy into harmless heat is also reflected by Y(NPQ) 33 , 34 . A high Y(NPQ) indicates that the absorbed light energy is excessive and that the excessive excitation energy is efficiently dissipated into harmless heat 33 .…”

“…However, not all PSII energy dissipation can be regulated through NPQ 33 , 34 . For instance, the non-regulated Y(NO) is made up of nonphotochemical quenching due to photoinactivation and constitutive thermal dissipation 35 .…”

Soluções tecnológicas emergentes para uma agricultura sustentável: microrganismos eficientes

“…A Fv/Fm é um parâmetro que demonstra o rendimento fotoquímico máximo do centro do fotossistema II (PSII), que está diretamente relacionado ao rendimento quântico da fotossíntese líquida das folhas das plantas (Figura 1). Neste sentido, em condições de estresse, especialmente estresse salino ou estresse hídrico as plantas tendem a aumentar a quantidade de CO 2 interno e diminuir a fluorescência da clorofila bem como a taxa de transporte de elétrons e o rendimento quântico efetivo da fotossíntese líquida consequentemente levando a uma baixa produção de grãos, por outro lado os estudos demonstram que o tratamento com ME promovem a manutenção dessas vias metabólicas permitindo a mitigação de estresses e promovendo o bom desenvolvimento das plantas [96,97,18].…”