scholarly journals Photosynthetic Product Allocations to the Organs of Pinus massoniana Are Not Affected by Differences in Synthesis or Temporal Variations in Translocation Rates

Forests ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 471
Author(s):  
Xiuxiu Deng ◽  
Zheng Shi ◽  
Lixiong Zeng ◽  
Lei Lei ◽  
Xuebing Xin ◽  
...  

Photosynthesis and the allocation of photosynthetic products are the two main factors that determine plant growth. To understand the growth and productivity of Pinus massoniana Lamb., the diurnal changes in photosynthetic rate were continuously monitored. Furthermore, the translocation and allocation of the photosynthetic products synthesized in the morning and afternoon were explored using 13C pulse labeling. The results showed that: (1) on sunny days, the diurnal variation of the net photosynthetic rate showed a “double peak” curve, with an obvious “a depression” when temperatures were highest and humidity lowest. On cloudy days, it showed an irregular “jagged” curve, which was curve consistent with the variations in photosynthetically active radiation (PAR). Meanwhile, the photosynthetic rate changed with the transient changes in environmental factors such as PAR, temperature, and humidity. (2) The mean value of the net photosynthetic rate in the morning was higher than in the afternoon, and the response of the net photosynthetic rate to environmental change (PAR, temperature, humidity, and CO2 concentration) in the morning was greater than that in the afternoon. (3) The translocation of photosynthetic products synthesized in the afternoon was faster than that in the morning. Shortly after synthesis of photosynthetic products, the translocation of products synthesized in the morning tended toward upper organs (including current-year leaves and 1-year leaves), while the translocation of products synthesized in the afternoon decreased in the upper organs. However, after 15 days of 13C pulse labeling, the allocation of the photosynthetic products synthesized in the morning and afternoon tended to be the same. These results indicate that the differences in the photosynthetic products synthesized and the temporal differences in the translocation rates did not affect the final allocation of the photosynthetic products in the various organs of the P. massoniana. These results improve our knowledge of the functional phases of P. massoniana during the diurnal cycle.

2011 ◽  
Vol 393-395 ◽  
pp. 1334-1340 ◽  
Author(s):  
Jie Zhang ◽  
Zhao Gang Liu

The needles' light dynamic response for net photosynthetic rate (Pn), the diurnal changes of net photosynthetic rates of annual Mongolian Scots pine and the relationship between of its Pn and environmental factors were studied in this paper by using LI-6400 portable photosynthesis system. Results show that needles at different positions of the crown have different light response for their net photosynthetic rate. Pn, photosynthetic saturated light intensity (PSLI) and light compensation point (LCP) of needles decreased from upper-crown through mid-crown to lower-crown. It suggests that different light dynamic responses of needles at different positions be related to micro-light environment to which needles acclimated in a long time. Diurnal variation of Pn showed a single peak. It had significantly positive correlation with stomatal conduction (Cond), transpiration rate (Tr) (at 0.01 level) and photosynthetically active radiation (PAR) (at 0.05 level), and significantly negative correlation with the intercellular CO2 concentration (Ci) (at 0.05 level).


Forests ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 18
Author(s):  
Xiuxiu Deng ◽  
Wenfa Xiao ◽  
Zheng Shi ◽  
Lixiong Zeng ◽  
Lei Lei

Carbon assimilation is reduced by stress. Under such conditions, the trade-off between growth and non-structural carbohydrate (NSC) storage becomes crucial for plant survival and continued growth. However, growth and NSC responses to drought and shading in Pinus massoniana Lamb. remain unclear. Here, we investigated the effects of drought, shading, and combined drought and shading on leaf gas exchange parameters, stem basal diameter, plant height, biomass accumulation, and NSC concentration in 2-year old seedlings after a 2 month treatment. The results showed that (1) both drought and shading significantly reduced photosynthetic rate, increment of stem basal diameter and plant height, and biomass accumulation, while NSC concentration increased under drought but decreased under shading; (2) the combined drought-shading treatment had a stronger effect on photosynthetic rate and growth than either stress factor individually, whereas the concentration of NSC did not change significantly; and (3) drought, shading, and their combination had a lower effect on biomass than on NSC partitioning, in which case clear effects were observed. Drought increased NSC proportion in roots by 5.4%; conversely, shading increased NSC proportion in leaves by 3.7%, while the combined treatment increased NSC proportion in roots by 5.1% but decreased it in the leaves by 5.4%. These results suggest that the mechanism inhibiting P. massoniana growth is different under drought and shading conditions according to carbon partitioning. Furthermore, complex environmental stress may lead to different mechanisms of carbon partitioning compared with either dry or shaded environments. Our findings will be helpful in predicting the impact of climate change on P. massoniana growth.


2011 ◽  
Vol 13 (1) ◽  
pp. 57-63
Author(s):  
You-fang Ding ◽  
Cai-yun Wang ◽  
Neo C. Mokgolodi ◽  
Xiao-xia Zhang ◽  
Ling-ling Shi ◽  
...  

2011 ◽  
Vol 343-344 ◽  
pp. 1087-1091 ◽  
Author(s):  
Lei Ma ◽  
Guang Xi Ren ◽  
Yan Shi

The effects of potassium fertilizer on diurnal change of photosynthesis in Stevia rebaudiana Bertoni had been studied. Diurnal changes of net photosynthetic rate (Pn) and environmental and physiological traits in leaves of Stevia rebaudiana Bertoni were measured using LI-6400 portable photosynthesis system. The results showed that optimal potassium fertilizer can increased chlorophyll content and improved photosynthesis rate and decreased the chlorophyll a/b ratio. At the same time, midday depression of photosynthesis abated or disappeared.


HortScience ◽  
1997 ◽  
Vol 32 (3) ◽  
pp. 515F-515
Author(s):  
Genhua Niu ◽  
Makio Hayashi ◽  
Toyoki Kozai

Potato (Solanum tuberosum L. cv. Benimaru) plantlets were cultured under four lighting cycles (photoperiod/dark period: 16 h/8 h, 4 h/2 h, 1 h/0.5 h, and 0.25 h/0.125 h) photoautotrophically (without sugar in the medium), and photomixotrophically (with sugar in the medium) in vitro for 28 days. Simulations of time courses of CO2 concentration in the vessel (Ci) and dry weight accumulation of the plantlets cultured photoautotrophically were conducted using a previously developed model (Niu and Kozai, 1997). While underestimation and overestimation of time courses of Ci in some treatments were observed, the simulated results of Ci and dry weight accumulation of the plantlets generally agreed with the measured ones. The difference of net photosynthetic rate response to Ci throughout the culture period was examined between the plantlets cultured photoautotrophically and photomixotrophically. Quantitative relationship between daily net photosynthetic rate (daily net production) and vessel ventilation rate per plantlet was simulated under various CO2 levels outside the vessel for given sizes of potato plantlets cultured photoautotrophically in vitro to aid appropriate CO2 enrichment and vessel design in commercial micropropagation.


1988 ◽  
Vol 31 (3) ◽  
pp. 375-378 ◽  
Author(s):  
Joginder Singh Manhas ◽  
N. P. Sukumaran

2012 ◽  
Vol 518-523 ◽  
pp. 4985-4993
Author(s):  
Si Jia Liu ◽  
Zhi Tong Zhao ◽  
Xiao Dan Yu ◽  
Hong Chao Li ◽  
Yun Wei Zhang

Lespedeza bicolor has developed root system and the ability of carbon sequestration, which can effectively improve the soil nutrient. We measured the correlation of net photosynthetic rate and physiological and environmental factors using space mutated Lespedeza bicolor of SP1 generation, the change of soil carbon and nitrogen content and microbial biomass was also discussed. The conclusion showed that the diurnal variation of photosynthesis was registered as double-peak curve and had "noon break" phenomenon. It showed strong ability of photosynthesis and its mean diurnal photosynthetic rates was 8.77 umolCO2·m-2s-1. Highly correlation was existed between net photosynthetic rate and atmospheric CO2 concentration ,the content of soil organic carbon and total nitrogen and soil microbial biomass displayed negatively relationship to the depth of the soil. Base on the study , we can conclude that the photosynthetic organic matter was effectively accumulated by Lespedeza bicolor of SP1 generation which made use of atmospheric CO2 and the root system located in the superficial soil has better potential of carbon sequestration.


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