Short basal internodes are important for lodging resistance of rice(Oryza sativa L.).Several canopy indices affect the elongation of basal internodes,but uncertainty as to the key factors determining elongation of bas...Short basal internodes are important for lodging resistance of rice(Oryza sativa L.).Several canopy indices affect the elongation of basal internodes,but uncertainty as to the key factors determining elongation of basal internodes persists.The objectives of this study were(1)to identify key factors affecting the elongation of basal internodes and(2)to establish a quantitative relationship between basal internode length and canopy indices.An inbred rice cultivar,Yinjingruanzhan,was grown in two split-plot field experiments with three N rates(0,75,and 150 kg N ha−1 in early season and 0,90,and 180 kg N ha−1 in late season)as main plots,three seedling densities(16.7,75.0,and 187.5 seedlings m−2)as subplots,and three replications in the 2015 early and late seasons in Guangzhou,China.Light intensity at base of canopy(Lb),light quality as determined from red/far-red light ratio(R/FR),light transmission ratio(LTR),leaf area index(LAI),leaf N concentration(NLV)and final length of second internode(counted from soil surface upward)(FIL)were recorded.Higher N rate and seedling density resulted in significantly longer FIL.FIL was negatively correlated with Lb,LTR,and R/FR(P<0.01)and positively correlated with LAI(P<0.01),but not correlated with NLV(P>0.05).Stepwise linear regression analysis showed that FIL was strongly associated with Lb and LAI(R2=0.82).Heavy N application to pot-grown rice at the beginning of first internode elongation did not change FIL.We conclude that FIL is determined mainly by Lb and LAI at jointing stage.NLV has no direct effect on the elongation of basal internodes.N application indirectly affects FIL by changing LAI and light conditions in the rice canopy.Reducing LAI and improving canopy light transmission at jointing stage can shorten the basal internodes and increase the lodging resistance of rice.展开更多
The morphogenetic responses to salt stress of TunisianPopu-lus alba clones were studied in order to promote their plantation in dam-aged saline areas. One year-old plants of threeP. alba clones （MA-104, MA-195 and OG...The morphogenetic responses to salt stress of TunisianPopu-lus alba clones were studied in order to promote their plantation in dam-aged saline areas. One year-old plants of threeP. alba clones （MA-104, MA-195 and OG） were subjected to progressive salt stress by irrigation during two consecutive years. The plants were grown in a nursery, inside plastic receptacles containing sandy soil and were irrigated with tap water （control） or 3-6 g/l NaCl solution. During this study, leaf epinasty, elongation rate, vigor, internode length, plant architecture, and number of buds were evaluated. Test clone response was highly dependent on the applied treatment and degree of accommodation.The most pronounced alterations were induced under 6g/l of NaCl treatment including leaf epinasty, leaf elongation rate delay, vigor decrease, internode length shortening, and morphogenetic modifications. These responses were less noticeable in the MA-104 clone with respect to the two other clones. The salt effect induced a delay in the leaf elongation rate on the MA-195 and OG clones leading to an early leaf maturity. The vigour and internode length of the MA-104 clone was less affected than the other clones. The OG clone was the most salt-sensitive thus, it developed shorter branches and more buds number than MA-195 and MA-104. The effect of long-term salt stress was to induce early flowering of theP. alba clones which suggests that mechanism of salt accommodation could be developed.展开更多
The objective of the present investigation was to evaluate the<i><span style="font-family:Verdana;"> Urochloa</span></i><span style="font-family:Verdana;"> Insurgent, ...The objective of the present investigation was to evaluate the<i><span style="font-family:Verdana;"> Urochloa</span></i><span style="font-family:Verdana;"> Insurgent, Piata and Signal grasses by varying the phenology in the attributes: stem population dynamics, tissue replacement, leaf:stem relation and weight per stem. The data were analyzed using a completely randomized block design with arrangement in divided plots and four replications, the procedure used was PROC GLM from SAS. The Signal grass presented higher stem density with an average of 450 m</span><sup><span style="font-family:Verdana;">?2</span></sup><span style="font-family:Verdana;"> stems, while the meadow with Insurgent grass registered the lowest stem density throughout the investigation, with an average of 320 m</span><sup><span style="font-family:Verdana;">-2</span></sup><span style="font-family:Verdana;"> stems;furthermore, in this treatment, the stem density tended to increase slowly over time (P = 0.05). The Insurgente and signal grasses showed rapid leaf elongation from day 21 of regrowth with 123 and 104 cm stem</span><sup><span style="font-family:Verdana;">?1</span></sup><span style="font-family:Verdana;">, while in Piata the accelerated leaf elongation was on day 14 with 113 cm stem</span><sup><span style="font-family:Verdana;">?1</span></sup><span style="font-family:Verdana;"> where it remained active its growth until day 56 (P > 0.05). As the regrowth age was increasing, the population dynamics of stems and weight per stem were increasing;in Insurgent and signal the leaf elongation and net growth increased to a maximum point to start declining;however, in Piata grass was increasing without decreasing. The trend of the leaf:stem relation was decreasing as the test progressed and senescence increased from day 21 of regrowth.</span>展开更多
基金supported by the Natural Science Foundation of Guangdong Province,China(S2012020011043)the National High Technology Research and Development Program of China(2014AA10A605)+2 种基金the Special Fund for Agro-scientific Research in the Public Interest(201503106)Modern Agriculture Industry Technology System for Rice in Guangdong Province(2016LM1066,2017LM1066,2018LM1066)the Swiss Agency for Development and Cooperation through its funding of “Closing Rice Yield Gaps in Asia” Project(CORIGAP)
文摘Short basal internodes are important for lodging resistance of rice(Oryza sativa L.).Several canopy indices affect the elongation of basal internodes,but uncertainty as to the key factors determining elongation of basal internodes persists.The objectives of this study were(1)to identify key factors affecting the elongation of basal internodes and(2)to establish a quantitative relationship between basal internode length and canopy indices.An inbred rice cultivar,Yinjingruanzhan,was grown in two split-plot field experiments with three N rates(0,75,and 150 kg N ha−1 in early season and 0,90,and 180 kg N ha−1 in late season)as main plots,three seedling densities(16.7,75.0,and 187.5 seedlings m−2)as subplots,and three replications in the 2015 early and late seasons in Guangzhou,China.Light intensity at base of canopy(Lb),light quality as determined from red/far-red light ratio(R/FR),light transmission ratio(LTR),leaf area index(LAI),leaf N concentration(NLV)and final length of second internode(counted from soil surface upward)(FIL)were recorded.Higher N rate and seedling density resulted in significantly longer FIL.FIL was negatively correlated with Lb,LTR,and R/FR(P<0.01)and positively correlated with LAI(P<0.01),but not correlated with NLV(P>0.05).Stepwise linear regression analysis showed that FIL was strongly associated with Lb and LAI(R2=0.82).Heavy N application to pot-grown rice at the beginning of first internode elongation did not change FIL.We conclude that FIL is determined mainly by Lb and LAI at jointing stage.NLV has no direct effect on the elongation of basal internodes.N application indirectly affects FIL by changing LAI and light conditions in the rice canopy.Reducing LAI and improving canopy light transmission at jointing stage can shorten the basal internodes and increase the lodging resistance of rice.
文摘The morphogenetic responses to salt stress of TunisianPopu-lus alba clones were studied in order to promote their plantation in dam-aged saline areas. One year-old plants of threeP. alba clones （MA-104, MA-195 and OG） were subjected to progressive salt stress by irrigation during two consecutive years. The plants were grown in a nursery, inside plastic receptacles containing sandy soil and were irrigated with tap water （control） or 3-6 g/l NaCl solution. During this study, leaf epinasty, elongation rate, vigor, internode length, plant architecture, and number of buds were evaluated. Test clone response was highly dependent on the applied treatment and degree of accommodation.The most pronounced alterations were induced under 6g/l of NaCl treatment including leaf epinasty, leaf elongation rate delay, vigor decrease, internode length shortening, and morphogenetic modifications. These responses were less noticeable in the MA-104 clone with respect to the two other clones. The salt effect induced a delay in the leaf elongation rate on the MA-195 and OG clones leading to an early leaf maturity. The vigour and internode length of the MA-104 clone was less affected than the other clones. The OG clone was the most salt-sensitive thus, it developed shorter branches and more buds number than MA-195 and MA-104. The effect of long-term salt stress was to induce early flowering of theP. alba clones which suggests that mechanism of salt accommodation could be developed.
文摘The objective of the present investigation was to evaluate the<i><span style="font-family:Verdana;"> Urochloa</span></i><span style="font-family:Verdana;"> Insurgent, Piata and Signal grasses by varying the phenology in the attributes: stem population dynamics, tissue replacement, leaf:stem relation and weight per stem. The data were analyzed using a completely randomized block design with arrangement in divided plots and four replications, the procedure used was PROC GLM from SAS. The Signal grass presented higher stem density with an average of 450 m</span><sup><span style="font-family:Verdana;">?2</span></sup><span style="font-family:Verdana;"> stems, while the meadow with Insurgent grass registered the lowest stem density throughout the investigation, with an average of 320 m</span><sup><span style="font-family:Verdana;">-2</span></sup><span style="font-family:Verdana;"> stems;furthermore, in this treatment, the stem density tended to increase slowly over time (P = 0.05). The Insurgente and signal grasses showed rapid leaf elongation from day 21 of regrowth with 123 and 104 cm stem</span><sup><span style="font-family:Verdana;">?1</span></sup><span style="font-family:Verdana;">, while in Piata the accelerated leaf elongation was on day 14 with 113 cm stem</span><sup><span style="font-family:Verdana;">?1</span></sup><span style="font-family:Verdana;"> where it remained active its growth until day 56 (P > 0.05). As the regrowth age was increasing, the population dynamics of stems and weight per stem were increasing;in Insurgent and signal the leaf elongation and net growth increased to a maximum point to start declining;however, in Piata grass was increasing without decreasing. The trend of the leaf:stem relation was decreasing as the test progressed and senescence increased from day 21 of regrowth.</span>
